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Hi,
I finally acquired a p1800ES (1973) about a month ago after quite some time admiring the P1800 series cars. I always liked Volvos and we do have a 1991 240 as well. It looks pretty decent in terms of rust and such since it is a California car, and for the interior it really only needs the front seats redone and eventually maybe the cracked dash. When I first got it and drove it it was running fairly well (I say this because I have no real way to compare it). The only thing I noticed from the start is that it had a slight hesitation from idle to acceleration and so I just drove it a bit more aggressively and that seemed to work well. It started right up and idled at around 900 when hot and all seemed pretty smooth.
After I bought it, I drove it for 45 minutes straight (including freeway speeds) while keeping an eye on the plethora of amazing gauges in the cockpit. Again all was well. Over the next few days I took it for a few rides along the coast etc, with the longest drive probably being around 2 hrs. Again, aside from the hesitations when driving it too cautiously it seemed to run fine. One of the symptoms of the hesitation would be on low acceleration (slight throttle) it would feel like it was in too high of a gear and jump/stutter/buck. With a decent amount of throttle/driving it slightly aggressively it seemed not to be a real issue.
As I like to fiddle with things and have been doing some mechanical work on my own cars for a while, I started to try and familiarize myself with the engine/system of this car and soon learned that (as many cars from the early era of fuel injection) there is A LOT to learn/troubleshoot. (And of course at the same time there is a lot of stuff that can go wrong or be out of whack and also many parts are hmmm lets say scarce and fickle). Of course the first few things I did was change the oil/filter, check all the fluids, pull the plugs to get an idea of how they look (all looked gray to brown which I felt like was decent, maybe on the lean side). I also changed the transmission oil just to see what I am working with. There are definitely some gaskets on the oil pan etc. that need to be addressed but after cleaning some of it and keeping an eye on any potential puddles, it doesn't seem to be an emergency.
After spending a few hours crawling google and various message boards I figured I should reset the throttle plate and throttle position switch and give it a good cleaning with some DeOxit D5 to try and start to set things up to spec and see if that helps the hesitation issues. After the cleaning I reset it according to the instructions (throttle plate ¼-1/2 turn open, TPS slightly more CCW after getting continuity on the bottom pins) and then went ahead and started the engine to see if anything had changed. The symptoms were still the same. I proceeded to clean it again and reset it once more just for good measure. I also wiggled most of the wires a bit and generally took a closer look at all the hoses and connections in the engine compartment. I noticed that a lot of the 'rubber boots' were falling apart and also some of the connector housings. Even though I could not see anything obviously 'wrong' it did concern me at the time. After fiddling with the TPS and throttle plate some more, I started the engine and I got a really high idle (like 2000rpm). I flicked the throttle a few times and got it to settle but some of the times it would just not settle back down.
During that time I also checked for a vacuum on the Auxiliary Air Valve when the engine was hot and realized that it was stuck open. (I found a used TPS and AAV on ebay and gave it a shot). I figured maybe the engine was running rich but pinching off the AAV didn't change anything. I unplugged the cold start valve and connected a pressure gauge to see where my fuel pressure was sitting. My gauge indicated 35 PSI so I adjusted the fuel pressure regulator down to slightly under 30 PSI (mind you it is a harbor freight one :)).
In the meantime the engine started to run somewhat rough (almost like an 8 cylinder or in other words not on all cylinders and was shaking at times when idling but still at around 900RPM). It now also didn't start up on first crank any longer and just generally didn't sound as healthy as when I first started fiddling with it :(. At this point I am not even able to drive it any longer as it has no power and dies as soon as I use the accelerator. I basically had to stumble home relying on the TPS to trigger some injections and riding the clutch so I could make it around the block at 5 mph in first.
I did a lot more googling and message board crawling and started testing some of the sensors with my DVM. I sucked on the tube to the MAP sensor and checked the resistances which checked out as specified. The coolant temp sensor and air temp sensor seemed within range although the wiring of the coolant sensor looked very suspect. (On a side note: Is this the same reading I get on my temp gauge?). I haven't tested the thermo time switch (?name) yet but am not sure that it would really affect how the engine runs once it runs. By now I had ordered a tune up kit with plugs/wires/cap/rotor/points/condensor/coil (not sure what kind of ballast I should get). I did test it with another blue Bosch coil with no changes but will install the new Lucas coil. The pickup points at the distributor (21/12/22) tested out ok as far as I can tell. Next up will be checking some of the connections at the ECU (Bosch 02800000340). I also ordered a bunch of housings and pins from repro parts in germany to eventually redo the injection harness as mentioned in several posts.
After installing all the tune-up parts and testing the connections to the ECU (which all seem good) it still runs rough. I keep thinking it is something to do with fuel delivery. I disconnected the large fuel filter but it was wide open and the fuel looks extremely clean. When I first start it after the initial priming through the pump it revs up to 1000 rpm and sounds great then falls back and just kinda struggles and shakes from then on. The only way it seems that I can affect it is by flicking the throttle open to trigger the TPS pulses and even then I have to do it fairly fast in order to get a sustained rev. It also seems that it doesn't really matter whether the engine is hot or cold. I will have to check the injectors now that the seals arrived with all the parts I ordered. What really gets me is that it all started after I cleaned the TPS and reset the throttle plate, which of course could be a coincidence but it just doesn't make sense to me after reading up on the D-Jet system. At this point it seems that the only thing left is a couple (partially) clogged injectors? Can valves that need to get adjusted be at the root? Why would it 'all of a sudden' be so bad?
Any help/insight would be much appreciated. I apologize for this horrendously long post. I tried to write down as much information as I could.
Thank you,
Stefan
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I have a 1970 1800E that I am experiencing a very similar issue. It starts easily but runs very rough with occasionally light backfire. Initially it had only 20 psi of fuel pressure which I increased to 29 psi. My main puzzlement is that I only have 6 psi of vacuum? All 4 of my plugs were black and fuel fouled. After I cleaned them and started the engine again, after 1 minute, they were fouled again! I am monitoring your progress in hope that you find a solution that I can resort to .
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Whale,
It sounds like somebody cranked the fuel pressure down in an attempt to correct an over-rich condition. My first suspect would be a failed manifold pressure sensor. Disconnect it’s hose from the intake manifold and suck on it to see if the MAP sensor diaphragm is leaking and not holding a vacuum. You have to suck, suck, suck on the hose to pull the diaphragm down. When you release the hose from your mouth you should be able to hear the diaphragm slide back home.
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Thanks for the tip. My problem is now resolved. The previous owner had blocked off the connection to the pressure sensor for some idiotic reason. Reconnecting the hose and raising the operating fuel pressure to 30 psi has my engine purring.
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Oh that’s good news! If it was a bad sensor those little jewels have gotten crazy expensive. Happy motoring!
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Volvo revised the fuel pressure to 31psi. Vacuum under 15 means that you likely have a leak somewhere around the intake system, including any rubber hoses. I guess you mean 6hg? Check and adjust you valve clearances.
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Stefan;
Congrats on the 1800ES and welcome to this forum!
That's a comprehensive recounting of your initial findings and work, and it sounds like you've got a good start...I presume you got the recommendation for cleanup and using the Deoxit from my SW-EM site, so you must have also seen the info for setting idle and links to the troubleshooting manual (Ref: https://www.sw-em.com/bosch_d-jetronic_injection.htm ). Checking and verifying sensor connections is good, but since you are just gaining experience with the D-Jet, I recommend only working on one sensor or item at a time, so that you minimize the possible uncertaintees when something afterwards is not right, and you have to check the "last item worked on". Remember also the D-Jet is an open loop system...there is no Lambda sensor checking the actual exhaust and making corrections to the injection, so the ECU calculates and actuates the Injectors based on sensor inputs, right or wrong...so it's crucial that they're right!
I would recommend you also check the Injector spray patterns to assure they are all clear and good...and install the correct replacement Seals for your configuration.
It wouldn't hurt to check and adjust Valves, but unless way out of adjustment, where there would be other symptoms, it's unlikely that they are the cause of poor running...its likely something with the FI Sys...remember pressure comes first and must be constantafter that, its sensors and connections, all of which should be clean and tight (that's where I recommend Anti-Corrosive Zinc Paste, NOT dielectric grease!, to keep all main Battery, Chag Sys, and FI Sys connections free of corrosion after bringing connections to shiny metal). Ref: https://www.sw-em.com/anti_corrosive_paste.htm Redoing the questionable harness pins and boots is a good way to keep questionable FI connections reliable. Parts of the harness are subject to thermal degradation in the engine compartment.
ECUs are highly reliable, but again, it wouldn't hurt to clean and preventatively treat the connector with Deoxit...
More later.
Good Hunting
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hi Stefan,
mine was very similar when i got it in 2014, flat out was 40 mph so i was pretty disappointed!
i started by draining and clean tank, re wiring the injectors and installing new inj and filters. Did you compression test and leak down? i would start with simple stuff like that first before tearing into injection system. When you do, you should disconnect and get 1 3 & 2,4 spray pattern, that together with good hot spark and good compression theres no reason you should get good power after engine is warmed up
hey Ron, hope all is going well
Rob
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Hi Ron and Rob,
Thank you both for your replies. I did a sort of compression test (I didn't have my real gauge at hand that stays at the pressure, just an air gauge). It did seem like they all went above 120 PSI though. I will do a more extensive test this weekend. I will definitely look at the injectors and the FI relay etc. I just read in a post that someone had a similar problem with low voltage so I will definitely check my battery and running voltage with alternator. Both at the battery as well as at the relay. Ron, I will get myself some of that zinc stuff and start going through all the connections also. I think the fuse panel could use some cleaning as well. I just reupholstered the passenger seat and it looks pretty decent for a first upholstery job so that was a good pat on the back :D. I also replaced some of the rubber seals (hood, hatch, window scrapers and in the process of redoing the door seals). So much to learn still and go through.
I will report back as soon as I have more information.
Thank you again!
Stefan
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Even if your compression numbers aren't dead accurate - what you show should be adequate for the motor to run nicely. I don't think you addressed ignition timing in your post. Make sure your advance is working. Depending on the year and motor, the B18/20 specs call for timing to be set at idle or 1500rpm. I set to maximum at a higher rpm to assure full advance - and that it isn't too far advanced if something isn't quite right. I use 32-35 degrees as a max.- Dave
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Hey Dave,
yes sorry, I did not mention that I reset timing to 10 BTDC. (staticly and also with a timing light). It is kind of hard as it is jumping around a bit due to the rough running condition and sustained higher rpm is not possible at the moment so hard to tell but I also moved the distributor around left to right but couldn't improve the condition. I figured at that point that it is probably not timing related (at least not mainly).
Best,
Stefan
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Timing spec is 10 deg BTDC set at 700-800 RPM with Vacuum governor disconnected
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Did you put the timing light on all 4 plug leads (individually) to make sure they all had consistant spark without interruption?
Also did you try pulling one plug wire at a time while the engine is running to see if there are any non-productive cylinders? If you find two dead cylinders then you want to go have a look at the trigger points.
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I have been pretty busy these last few weeks, but I did hook up the timing light to each lead and got a continuous flash off of each one (great tip btw). I don't think the trigger points are a problem at this point since I did test them with the distributor out and on the bench. I also removed the injectors and cranked some fuel into some glass jars. The amount appeared fairly even although I wouldn't know if it is the 'right' amount. I got some materials to create a new injection harness. Hopefully I will find the time to do that soon and then retest things. I will report back as soon as I have more info.
Thanks all for the great feedback!
Stefan
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Just to give an update. I also posted on Swedespeed and I am a bit more active there. I checked the tank for crud, looked clean. I checked the injectors, seemed clean but I will have them cleaned just to be sure. I made a new wiring harness for the fuel injection (basically from the firewall out). I got the plug cases from europarts and the pins as well. I ordered a coolant temp sensor (when I have it unplugged it runs much smoother and the resistance seems a bit low on the testing). I am slowly working my way around fixing things here and there and working on cleaning some of those contacts (adding zinc stuff to the cleaned connection as suggested by Ron). Will keep this updated with any changes/headway for anyone who may run into problems like mine on a '73 ES.
Best,
Stefan
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Unfortunately no real update. The new coolant temperature sensor didn't solve anything. I removed the injectors and will hopefully get them cleaned this week (the paperwork from the PO states that they were replaced in 2018 so not sure that will do any good. They look like Beck and Arnleys but not positive). I adjusted the valves, they seemed a bit tight. Should all be close to .016 now. When I removed the spark plugs to make it easier to adjust the valves I noticed they were all fouled now (replaced them when I started to fiddle with everything). This seems weird as I assumed that I was not getting enough fuel. I am somewhat confused about this. Will update as I keep moving forward.
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Compression seems ok, 116, 118, 120, 120 (cold 1 through 4).
I got about 10 in of HG vacuum at the rough idle of around 6-700 rpm.
Going to empty tank next and inspect and also change the in-tank filter.
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Hello,
Both your compression and vacuum readings are low.
Before you dump anymore money, I strongly suggest you perform a cylinder leakdown test.
This will help you determine whether the engine needs to be rebuilt.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com
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A question for the experts:
Whenever I hear of compression numbers that are consistently low across all cylinders along with the vacuum being low I wonder if the cam timing is off to where the intake valves are open too long and overlapping too far into the compression stroke.
Is it possible for the cam gear to slip on the center hub a bit but not totally separate? Or maybe a sheared woodruff key? Can the cam vs crankshaft timing be verified with a dial indicator on a tappet?
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Once the steel centre, it's vaguely star shaped, starts to come loose from the fibre cam wheel things get very noisy, so if that isn't the case I'd not think that it was an issue. Compression numbers are indeed very similar. A good sign but I'd do a wet compression test with some oil and see what the difference was. Had the car been sitting for a long time before purchase? Bores could have been a bit rusty and the rings may be partially stuck but still giving similar numbers. Are the valve clearances correct? That might have been mentioned already.
Vacuum at what rpm? 10 at 600 might increase to about 15 at 900 which is acceptable.
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I will do another compression test this weekend as well as a leak down. The vacuum was at rough idle at around 5-700 rpm. I will try to get a more accurate vacuum test done this weekend as well. What still bugs me is that when I first crank the engine cold it fires up and sounds great then immediately goes to a rough idle or dies which leads me to believe that fuel delivery would be the issue. We will see what the numbers can tell us. I may be able to empty out the tank this weekend and take a look inside and replace the filter as well. As I mentioned in my first post, I do have constant fuel pressure at the rail (could it still be the fuel pump?). (Will a MAP sensor that has a leaky diaphragm cause a rich or a lean condition?)
Thank you all for the input!
Stefan
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A MAP sensor with leaking diaphragm will cause the engine to run super rich. That could explain why it will fire up just fine when cold, when a rich mixture is needed, but then starts to run rough as the engine heats up.
Does the exhaust spew black smoke or overly stinky eye-watering fumes?
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Does the idle rpm increase when the engine is warm? If not, can you adjust it up to about 900? Cold idle that low may mean that the cold start valve is not working. Look at it as a sort of choke function. Idle adjustment is under the front of the inlet manifold. Don't try and increase the idle anywhere else.
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Keep in mind that the cold start valve should only inject fuel while the starter is cranking AND the thermal timer senses a cold engine. Both those conditions must be met in order to get any cold start injection. Now, if the wiring was somehow all screwed up and you’re getting cold start Injection outside of those conditions being met then the engine will start just fine when cold but will almost immediately start chugging over-rich.
Try disconnecting the wires from the cold start valve just to see if it helps. Better yet, try unplugging the wires AND cap off the fuel supply line to the cold start valve. I had a valve one time that stuck open and continued to shoot fuel without any electrical input.
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Fuel pressure should be 31psi. Normally quoted as 30psi but apparently Volvo upped it to 31psi on one of their info sheets. Doubt if anyone noticed any difference! Might have been due to a change in injector type or maker.
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posted by
someone claiming to be c1800
on
Tue Oct 6 21:41 CST 2020 [ RELATED]
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"Fuel pressure should be 31psi. Normally quoted as 30psi but apparently Volvo upped it to 31psi on one of their info sheets"
Not exactly, the original spec was 28 PSI, and they upped it to 30 PSI in a service bulletin.
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A Volvo mechanic I had many years ago said they used to bump the fuel pressure up a bit on the D-Jets to help eliminate pinging.
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