hi,

i have a 1983 240gl b23e which has recently developed a cold start problem. It used to start almost immediately all the time. Recently it takes up to three ignition attempts to start. Sometimes this is associated with rough idling for a few seconds and/or hesitation on acceleration shortly after.

The fuel pumps both seem to be working ok. The fuses are intact. Coil, plugs, dc all ok. The car had a rain leak through wiper motor and since i recently changed the w/s intermittent relay (damaged) the fuel pump/injector relay was the likely culprit.

So, my FI relay clicked upon ignition attempts. I have scoured up a couple of decent looking ones from the wreckers for $5 and they all seem to work in a similar fashion. Are they meant to click on ON or only when IGNITION? Would this be the cause of the cold start problems.

The car runs like a dream otherwise. And it starts first-go once a cold start has been succesful.

Thanks for any help.

Chez

" Are they meant to click on ON or only when IGNITION?"

There are actually TWO FI relays for the LH 2.0. The "System" relay turns on with Key ON to power up the AMM and ECU.

The "Fuel" relay (BL/GN wire on terminal 85) is turned on by the ECU (grounding the BL/GN wire), but ONLY when it senses Ignition Pulses from the Coil negative (terminal 1).
The Fuel relay powers the Pumps, Idle Air Control, and Injectors.

You didn't say where you are, but Cold temps might affect connections at:

° 25 amp blade fuse near the coil (feeds input 12V to both relays)
° Both Coil primary terminals
° Fuse 12, in the "pick" to the Fuel relay
° FI system ground points on the intake manifold

Also check for air/vacuum leaks that may be leaning out the cold starting fuel mixture. The underside of the AMM-to-Throttle duct is often overlooked.
--
Bruce Young,
'93 940-NA (current)
'80 GLE V8 (Sold 5/03)
'83 Turbo 245
'76 244 (lasted only 255,000 miles)
73 142 (98K)
'71 144 (track modified--crusher bound)
New 144 from '67 to '78
Used '62 122 from '63 to '67

hi,

thanks lucid. i will have a look at those things you mentioned. But first, where abouts is the system relay? And I am a little confused as to what fuel injection system I have (K-jet LH jetronic)...I am referring to the Haynes manual and I am confused. I cannot see an amm where they say it is supposed to be. Is there an easy way to tell if I do have the LH 2.0?

I am in Brisbane, Australia...28-34 C in summer (now).

The fuel injection relay I have in my car is 1235337.

Thanks,
Chez

Hi Chez,

"The fuel injection relay I have in my car is 1235337"

OK—that's an (early) K-jet relay. Probably Black, or even metal case? Later ones are gray, green, or red. That's the only one for K-jet.

Theoretically it should NOT click with Key ON, but some do, depending on where the distributor stopped on the last shut down. It requires Ignition pulses (R/W wire from Coil negative post) to stay energized.

But I'm thinking now that Bob's Check Valve tip is worth testing out. It's right at the pump and should keep pressure in the line for several minutes. (But not ovenight.)

Anyhow, a quick way to buzz the pumps before starting (as test) is to apply 12 V to Fuse 5 (electrically, that's the same as the FI relay output). The most common way is to jumper from Fuse 6 or 7 (6 thru 10 are hot all the time). Use a piece of wire or whatever. I've used an open pair of narrow nosed pliers.

It's best to work on the INPUT fuse contacts, the ones closest to the door. This avoids excessive current thru Fuse 5. Run them for 5 - 10 seconds, then see if the cold start is quicker.

Is your Haynes a Green cover 1974 -1990, or the later Blue cover?

Bruce




--
Bruce Young,
'93 940-NA (current)
'80 GLE V8 (Sold 5/03)
'83 Turbo 245
'76 244 (lasted only 255,000 miles)
73 142 (98K)
'71 144 (track modified--crusher bound)
New 144 from '67 to '78
Used '62 122 from '63 to '67

hi,

thanks a lot for your help.

so i have a k-jet. do i need to worry about the 25amp fuse, the system relay etc or did that only apply to LH systems?

i will follow up on bob's advice. my hayne's manual doesn't tell me where the fuel pump check valve is or whether it is easy to remove or not. do you think it is? how much is a replacement going to set me back?

i will continue to try and fix this problem.

thanks,

chez

Hi chez,

do i need to worry about the 25amp fuse?
No, that's for LH. And the relay you found is the only one for K-jet.

i will follow up on bob's advice".
"my hayne's manual doesn't tell me where the fuel pump check valve is"
As I said, it's right at the pump outlet.
And again, which Haynes do you have? Knowing that, I might be able to help you better.

"or whether it is easy to remove or not"
"easy to remove" is relative, but I can't say, not knowing your experience level, what tools you have, etc.

"how much is a replacement going to set me back?"
The Bosch # is 1-587-010-539, costing $12 US at FCP Groton.
But we don't even know you if need one yet. Did you try the fuel pump "pre-start running" I suggested?
If that helped with the Cold Start, it could possibly point to the check valve.
(I'm trying to help you diagnose what's actually wrong before you spend money needlesly.)

It sounds like a Fuel problem. But that could be either Low Pressure, or Low Volume. There are several possible causes for each. I don't know how far we can go with trouble-shooting because the diagnosis depends on:

1)available test equipment (pressure gauge, digital volt meter, basic tools. etc.),
2) the experience/ability to use them ,
3) reference manuals.

I have simple Low Volume test you can try, but I need to know the outcome of what I've already suggested, and more about items 1, 2, and 3 above—so we use our time well, and I don't lead you into trouble.

Bruce
--
Bruce Young,
'93 940-NA (current)
'80 GLE V8 (Sold 5/03)
'83 Turbo 245
'76 244 (lasted only 255,000 miles)
73 142 (98K)
'71 144 (track modified--crusher bound)
New 144 from '67 to '78
Used '62 122 from '63 to '67

hi,

the cold start is quicker with the fuel-pump engaged prior to starting.

chez

hi,

the fuel pre-pump test worked this morning. then the car kicked over fine, first go.

i have a lot of general tools, ramps, jackstands etc and a digital multimeter and a couple of more specific tools but no pressure gauge.

I will try the pre-pump trick again this afternoon once the car has cooled right down and i will get back to you ahortly thereafter.

thanks a lot for your help.

chez

ps i have the red haynes manual 1979 -1990 240s. it tells me how to remove the fuel pumps etc and there possible locations. not a lot about the check valve though.

Hi chez,

the fuel pre-pump test worked this morning. then the car kicked over fine, first go.
That's a good sign. But I'm not real sure about the Check Valve theory, because it isn't meant to hold pressure overnight (the test is for 20 minutes). I think it's more apt to be a "delivery" problem.

I'd like to start by testing fuel pressure, but with K-jet it requires a special guage/valve set-up. So the best we can do is go after the "usual suspects" by other means. Here are the things we can test:

1) Fuel Delivery Volume. (You could use some help with this, or a long pair of wires and a switch so you can control the fuse 5 jumper from the engine area). A neater way is to rig a pair of switched wires plugged into FI relay harness terminals 30 and 87/2, with the relay removed. (Even better if you add a 10 amp fuse in the line.)

If Delivery Volume is low, it could be due to low pressure, but we can still test...

2) ...Both pumps for running (pull fuse 5 and put 12v to left contact for Main pump, then right contact for Tank)

3) The current draw for each pump (if your meter can measure at least 10 amps of current), using the meter between 12V and the fuse 5 contacts as above. (Main pump is 9.5 amps maximum. A weak pump will be lower, I believe. The Tank pump, should be 1 to 2 amps.)

4) A short hose in the tank, which connects the "prepump" to the outlet pipe. Over time. this hose rots and leaks, which reduces the output flow to the Main pump (even with a full tank)—and causes the Main to suck air if the tank level is below half.. This is not a fun job, but given your tool kit, I'd say you're up to it. And, given the age of the car, it's quite likely to be needed.

Here's how to test fuel delivery:

A) Loosen the tank filler cap, and disconnect the fuel Return hose, where it conncts to the return pipe. I'm hoping it's in the usual K-jet location, just below the filter on the firewall left side. Have a rag handy to trap any fuel spray as the connection opens.

B) Put the end of the return hose into a 2 liter plastic bottle. Also set your meter to monitor battery voltage during the test period.

C) Start the pumps, and when fuel appears, start measuring for 30 seconds, then stop the pumps. Try to note/mark the fuel level at the 30-second point, as some flow will continue after the pumps stop.

Assuming 12 volts at the battery, the quantity should be 1 Liter.

Lets leave it at that for now. Let me know how it goes.

Bruce
--
Bruce Young,
'93 940-NA (current)
'80 GLE V8 (Sold 5/03)
'83 Turbo 245
'76 244 (lasted only 255,000 miles)
73 142 (98K)
'71 144 (track modified--crusher bound)
New 144 from '67 to '78
Used '62 122 from '63 to '67

hi,

i went ahead and tried the 30s test using the delivery line before the fuel filter. i got a litre easy this time. i changed the fuel filter 22000k ago. the main fuel pump looks pretty new beside the accumulator. the people i bought the car from said it was replaced, but i don;t know how long ago. i will ask them about this as i bought it from a friend's mother.

hopefully it is the fuel filter. cheap replacement ($15).

thanks,
chez

hi,

i went ahead and tried the 30s test using the delivery line before the fuel filter. i got a litre easy this time. i changed the fuel filter 22000k ago. the main fuel pump looks pretty new beside the accumulator. the people i bought the car from said it was replaced, but i don;t know how long ago. i will ask them about this as i bought it from a friend's mother.

hopefully it is the fuel filter. cheap replacement ($15).

thanks,
chez

hi bruce,

i was wondering if the fuel filter might be clogged. i did replace it about 30000k ago. but i am unsure how long it went before that. am i able to do the same 30s test by taking off the delivery line instead of teh return line?

also, if i do need a fuel pump i am going to the wrecking yard. here in australia a new fuel pump costs $288 a second hand (not reconditioned) costs $132, through a second hand volvo dealer. if i went straight to the wrecking yard i know i could get one cheaper. and i do have a car in mind. it has several parts i will probably pinch. a coil, which i will test; an ignition module (unsure how to test this, any hints?) and the main fuel pump (which i will most likely test between two buckets of fuel or with aq multimeter if possible?). I never new volvos could be so expensive.

Oh i had a look at my pump and the electrical contacts are a ok.

cannot wait to hear what else you have in store for me.

thanks,
chez

hi,

ok so i performed the tests and here are the results.

oh, on my fuel relay i had to ground 30 and 87 b/c there was no 87/2.

battery 12V (phew)
both tanks operational
in-tank pump current 1.59A
main fuel pump current 4.5 -4.6 A
30s test gives about 0.5L

Does this mean I have to replace the main fuel pump?

thanks,
chez

Chez,
Trying to answer 3 posts at once, in time sequence. Hope it's not too muddled...

1) on my fuel relay i had to ground 30 and 87 b/c there was no 87/2.
Right—my goof (later relay) Just going to 87 is enough for pumps. 87b powers heating elements in Control Pressure Regulator and Aux. Air Slide (not needed for pump test/running)

2) battery 12V (phew) OK
3) both tanks operational GOOD (but that tank pump hose or filter sock may still be suspect)
4) in-tank pump current 1.59A GOOD
5) main fuel pump current 4.5 -4.6 A MAYBE sign of weak pump. But if pump looks recent, suspect voltage losses in connections leading to pump. Test by measureing voltage AT PUMP when running, and compare to battery voltage (should be little difference. Maybe 0.5v???) Not sure, but check it out before condemning pump.
Could also be a poor pump GROUND connection (under back seat I think). Check/clean all connections (can you use the Haynes diagram?). Then check the running Voltage AND current draw to see if either/both have improved.

6) 30s test gives about 0.5L. NOT GOOD, unless tested at RETURN LINE as the manual specifies. For some reason, they want to see the volume coming OUT of the Fuel Distributor (NOT going in).

7) Does this mean I have to replace the main fuel pump? MAYBE, but could be due to a clogged TANK pump filter sock and/or that short in-tank hose, as mentioned in #3. As a crude test of overall Tank Pumping, take the line off again at the Fuel Filter output, rig it to your container, and run the Tank Pump with 12V to the Fuse 5 Output (right) contact (Fuse REMOVED).

After about 10 seconds you should see a good, steady stream about as large as the hose/line inside diameter. If it's much less, it's likely to be the tank filter sock or a rotton hose. Only way to be sure is to pull the Gauge Sender/Pump unit and check.

8) i was wondering if the fuel filter might be clogged. i did replace it about 30000k ago. OK, they are good for 75,000 miles or more, in my experience..............(but see #13)
9) am i able to do the same 30s test by taking off the delivery line instead of teh return line? NO (see #6)

10) i am going to the wrecking yard...and i do have a car in mind. i will probably pinch. a coil, which i will test; an ignition module (I wouldn't bother with either one. Never failed me.) and the main fuel pump, which i will most likely test between two buckets of fuel or with aq multimeter if possible? (Sounds possible, but be careful about sparks & fumes).
11) I went ahead and tried the 30s test using the delivery line before the fuel filter. i got a litre easy this time DON'T THINK IT COUNTS (see #6)

13)hopefully it is the fuel filter. cheap replacement ($15) At that price it may be an "off brand" that doesn't last like a Bosch. Go for it.

Bruce
--
Bruce Young,
'93 940-NA (current)
'80 GLE V8 (Sold 5/03)
'83 Turbo 245
'76 244 (lasted only 255,000 miles)
73 142 (98K)
'71 144 (track modified--crusher bound)
New 144 from '67 to '78
Used '62 122 from '63 to '67

sorry. 11.39V across in-tank fuel pump (12.3V across battery)

i couldn't get the fuel lines off to get a look inside the tank for the pump and hose/sock. but the car never cuts out low fuel rounding corners which would be expected if the hose was stuffed.

i'm a little over getting to the bottom of this problem. so is my girlfriend :(. but i have to finish it.

thanks,
chez

hi,

main fuel pump ground looks fine. and all wires intact, contacts clean at fuel pump. voltage across here is 11.39V (battery is 12.3V) i just unplugged the connection to the fuel pump from under the seat and placed a voltmeter across ground and on the positive? was this right, i thought it would be easier than trying to voltmeter across the connections from under the car (also near fuel).

then, the in-tank fuel pump 10s test. i just left the main fuel pump unplugged, disconnected the return line (like the one for the 30s test) and jumped 30/87 on my relay. i wasn;t getting much joy from the in-tank pump. i could here it. the amperage is correct. but no fuel entering the tank.

yep, just checked again. nothing when running the in-tank pump.

what next? i suppose i should have a look at the in-tank pump.

thanks,
chez

Chez,

"then, the in-tank fuel pump 10s test. i just left the main fuel pump unplugged, disconnected the return line" WRONG

The test is made at the Filter output, not the return line (see step #7 in previous post). For the little tank pump, the full system resistance (at the Return line) is too much.

Maybe, since the original problem—slow starts—seemed to go away when you buzzed the pumps before cranking, the easiest thing for now would be to just keep doing the fuse jumper bit. Or maybe rig it up to a switch on the dash. My cars used to have a lot of such "custom" wiring.

Since Fuse 7 is the input to the FI relay (and thus, the Main pump fuse) I'd wire from the Fuse 7 output (red wire) to Fuse 5 input (Y/Red wire), with a switch in between.

Or just connect the wire to fuse 5 input, and manually touch the free end to fuse 7 for "priming".

Bruce
--
Bruce Young,
'93 940-NA (current)
'80 GLE V8 (Sold 5/03)
'83 Turbo 245
'76 244 (lasted only 255,000 miles)
73 142 (98K)
'71 144 (track modified--crusher bound)
New 144 from '67 to '78
Used '62 122 from '63 to '67

hi,

thanks a lot for your help. i will see how the car goes now that i have cleaned up a lot of the electrics. if it still struggles i might just install a switched jumper to prime the lines.

many thanks,
chez

hi,

you did a great job answering all those posts in sync!

well, i will test the voltage at the fuel pump and i will check and clean the fuel pump ground under the rear seat. also, i will try the in-tank fuel pump volume test.

i will get back to you with some info shortly.

thanks,
chez

Fuel pump check valve???
--
-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel