hi all, car is 85 244 turbo intercooler c.i fuel inj. car came with this wiring modification to the fuel pump relay, i will describe it.
terminal= 31 black wire to overpressure switch unhooked from relay.
terminal= 87a yellow red wire (the larger of the two) has a wire spliced into it and ran to fuse # 7 with a toggle switch in line to shut off power to 87a. each yellow red wires feeds a fuel pump.(per bentleys) i must use toggle every time i start and stop engine.
being no wiring wizard here is what i do. and without a vacume guage and remote r.p.m. guage to test items (per bentleys) i unhook toggle switch power feed from fuse #7 to 87a (the jury rig) and hook up overpressure switch black wire to terminal #31 on fuel pump relay results= everything seems to be fixed, but not for long car runs like do do and blowing black smoke, relay is very very hot. i dont understand terminals 31b 15 or 31 and their purpose. (keep in mind im a plumber good with wrenches bad with wires) i put all wires back like they were to begin with and runs great, cool relay, but back to using toggle=sucks.
i have tried three fuel pump relays from boneyard and also a overpressure switch. can someone help me. i hope this is obvious to someone out there. thanks for everything. its only easy if you know how to do it ;^!
four volvos. 2= 85s, 86, 87,
1990 740 turbo R.I.P.

thanks to all. this will give me a starting point to reasearch and learn more about the c.i. system. i'll be back

Mike,
I have the green book diagram and what you discribe is by-passing the relay (5 to 7 on fuse block) only on the relay contacts and blocking the relay operation by removing lead 31. The two fuel pumps run off of 87 but the in tank goes through fuse 5 to the pump. The contacts you discribe do the following:

87- Feeds fuel pumps through the operating relay from fuse 7
31- Shuts off the relay when turbo boost pressure is to high. This stops fuel from flowing and is either on or off. When it is removed the relay will not operate.
31b- Spark sensor lead for the relay to operate, It comes from pin1 of the coil. No spark signal, relay shuts down and no fuel.
15- This is the voltage for the fuel pump relay winding circuit only, not for the pumps. This is from Fuse 13 which is used for other things like the CIS circuit.

On my 82 non- turbo the total current flow from fuse 7 (taken across the fuse holder with fuse removed) is about 9-10 amps. The main pump uses about 7 and the tank pump about 2. If this reading is higher than say 11 amps, put amp meter across fuse 5 with fuse removed and you should see about 2-3 amps for the tank pump. If tank pump is ok then your main pump is drawing heavy.

What my be wrong is the relay can not handle the current flow and is causing erratic fuel flow when it heats up. When it is bypassed by the switch, pumps run normal. I have the diagram if you need some help. Good luck.

Mario


PS By removing lead 31 the PO was able to disable the relay without effecting other circuits.

hi there and thanks to all. i will get my friends meter tomorrow (fluke) mine does not test for current draw in dc amps. i couldnt get it today worked late. what you describe here sounds like a easy start, and i can do this first. although im willing to try anything that is suggested on this thread. the new wiring harness (ipd) was installed by me about one month ago, also i have two extra computers talked about in the thread but they are junkyard parts (not tested) so this relay situation was like this before i installed new harness. i have cash to buy both new pumps. and there is a 83 240 turbo down at the boneyard if i needed any parts to swap out. i know there are some differences from reading bentleys. i allready am learning about the c.i. system from this thread. i appreciate everyones help. this could take me a few days to follow suggestions but i never give up=hardknocks

31b is white/red-tach signal from coil. when car stalls, this opens the relay, stopping pumps.

31 is black wire-ground for the relay. in the turbo, if the boost is too high, the switch opens and removes the ground.

15 is blue/red wire-power to the relay from the ignition switch.

87 is yellow/red-power to the pumps.

87b is blue-power for the lambda relay and the control pressure regulator heater circuit.

30 is red-power for the pumps when the relay is closed.

off hand, i'd say the relay is heating up from too much current draw. they WILL get warm under normal operation. how hot is hard to judge from here. good luck, chuck.

Chuck,

Nice to know that you know all that! You can park your fanny in my bay anytime! Riddle me this, since he is having a problem with it running rich when he hooks it up the right way, I'd suspect somebody was bypassing a failing CIS computer. If it were a bad 02 sensor, a bad frequency valve or frequency valve relay, or a warm up regulator, wouldn't they have just disconnecting the irritating component? But since the CIS computer plays into the signal for the fuel pumps, it can't be silenced that easily. I've had ON VERY RARE OCCASIONS, these computers fail, and either make the run full ass rich, or zap the main fuel pump fuse. Of course this is assuming the person who "rigged" it never tried just unhooking a warm-up regulator or frequency valve. Your thoughts?

Chris

Porkface/Chuck - I think we're going down the wrong Bunny Trail here because Chris used "CIS" where it should have been "CI". CI is Volvo's shorthand for the Continuous Injection system, so I think that's what he refers to - a bad computer in the O2 sensor/frequency valve loop.

There is indeed a separate, small "CIS" (Constant Idle Speed) computer on these K-jet cars, and as you point out, all it does is drive the IAC motor depending on the RPM signals it gets from the coil primary, plus the coolant temp sensor, and A/C microswitch.
--
Bob (son's 81-244GL B21F, dtr's 83-244DL B23F, "my" 94-944 B230FD; plus wifemobile Dodge minivan, hobbycar MGB, and numerous old motorcycles)

might be my bad-assuming!!!! everyone speaks the same language as i. had she been doing lotsa euro cars over the years, i would've bet cis was american for kjet. seeing as it's only volvos, i figured it was constant idle system, which is volvo-speak, straight from the factory manuals. seeing her other post on the thread, looks like you're right. but it still begs the question, how does the lambda ecu control the mixture that much. i need to get my hands on things like this. and so it goes, chuck.

how does the lambda ecu control the mixture that much.

I don't see how the lambda is controlling anything if he's been running with the relay bypassed (and castrated at 31). Ther would be no voltage from 87b to pick the lambda relay.

--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

hi bruce after five minutes of driving the car runs rich and is intermittently trying to cut out when i wired the relay like the bentleys shows on page 240-8 that would be the correct way. but when i put the jury rig back together it runs fine.

...when i wired the relay like the bentleys shows on page 240-8...

Mike, I don't like to make this thread any longer (tried to email you direct but url didnt work), but wanted you to know that Bentley 240-8 diagram is NOT complete. You did good to find it and do what you did. But the whole Lambda ECU (O2 sensor etc.) is missing. It gets activated from Fuel relay point 87b, but isn't shown at all on 240-8.

Assume there is a Blue wire coming off that little square where the 87b Blue wire heads north to the WUR/CPR.

Then to see the tie-in, go to page 390-29, grid N-2. Item #159 on the right is the "Lambda relay" and it should get picked at terminal 86, by the blue wire from 99/87b, which is your Fuel relay (also shown back at grid B2/3). ALL of this major stuff on 390-29 is missing on 240-8, and I think it may be key to the rich problem that you get when you got the Fuel relay to working.
The Lambda relay is a cube out on the left fender rail near the hi/lo relay.

--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

when the relay is wired correctly, the car runs rich. there's the rub. chuck.

when the relay is wired correctly, the car runs rich. there's the rub.

I made a stab (or a stretch) at that in my post at the bottom. He has replaced his harness. The WUR and Freq Valve plugs can be easy to mix up.

If those plugs are switched, with relay and Lambda working he would be putting constant voltage on the FV and holding it wide open.

Like I said, it's a stretch. But it happens (don't ask).
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

What you said could very well have happened. However, the previous owner is who "reconfigured" the relay. So for this to fly, the wiring harness would have had to have been done by the previous owner, who then "reconfigured" the relay. So...yep...hardknocks...if the wiring harness was new prior to your becoming the owner...look there first.

Chris

Chris,
I'm either missing something, or failing to make my point...

1) PO didn't just "reconfigure" the FI relay, he "killed" it by removing the ground on terminal 31 (and thus killed the Lamba operation)
2) Mike installed the new harness "about a month ago" (no problems noted)
3) Mike's rich-running problem began as soon as he restored the FI relay operation. My "guess" is that ...

A) The newly working FI relay also restored the Lambda operation.
and
B.1) Restored Lambda operation + mis-connected WUR/FV plugs would drive FV wide open causing "black smoke"
or
B.2) Restored Lamba operation + maladjusted mixture at F. Dist (by PO, to run with no Lambda) could cause rich-running

But all (my current) bets are off — If PO somehow kept Lambda working with NO FI relay. Still too many unknowns for me.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

chris-i know where to get the wiring diagram, not from memory. do you mean constant idle system-volvo cis? i don't see where the cis ecu has mixture or fuel pump control. unless we're at a bad harness somehow. if it's the idle ecu, what's the idle motor doing? the idle ecu gets power from 15, on the same wire, like the fuel pump relay. maybe the idle motor is shorted? it shouldn't cause the relay to heat up from too many amps. these "quagmires" need to be seen. like i always say, i can't see under your hood, the light here sucks. i'm curious how your examples on the rare occasions, were cured with the idle ecu. my experience has been 2 idle ecus, for shorting out from harnesses and no idle motor control. new harness and ecu and the car now idled. never saw mixture problems. how did you arrive at the conclusion? i'm curious now! lemme know, please. seeya, chuck.

hi chuck if it helps the harness i removed was about 80% bare wires throughout the entire length. i was suprised it even ran but when it rained the car didnt run.

Jeez, I hate wiring diagrams. They fail to show you everything. Of course, the only CI Fuel Injection System book I have (can find) is for the 78-80. Anyhow, not the little two connector computer (CIS), but the larger one (CI)that sits above it. I should never attempt to answer questions when I'm tired! For the car I had the running rich problem on, it was the CI computer. For the car that was zapping the #13 fuse, it was the CIS computer.

I'm not EVEN saying that the computer is the problem since I don't know how extensive the previous owner's or the previous owner's tech's volvo knowledge was. I do suspect though, that the modification occurred to provide power to the pumps, and while doing so eliminate enrichment problems. The only component that I can see going through this bother for would be the computer UNLESS someone didn't have the knowledge to just unhook or replace whatever component was really causing the problem.

If memory serves me, isn't there two "switches" that look alike? One for acceleration enrichment, and one for overload protection. The disconnected black wire WOULD, in theory, be what someone expected the problem to be. Maybe the car was overboosting and killing the power to the relay, and the bypass was set up for that. Maybe they thought they were bypassing the enrichment pressure switch, not the overload protection switch. Maybe there were two problems. It usually is when it kicks your butt.

Chris

if it helps, brand new engine wiring harness, cleaned idle cont valve, new thermal time switch, f.i. temp sensor, coolant temp sensor, fuel injector o rings. runs great when relay is jury rigged.

hi there i am not good at troubleshooting this type of thing, i have a little common sense and read alot. i have some extra parts also. the main pump is noisy compared to my n.a. volvos. i can borrow a fluke tester to check current draw probably tomorrow. i have bentleys and i like to learn new things. but probably wouldnt start troubleshooting at the right place. let me know what you would do first and i will give her a go. i also have a few dead presidents saved up to help things along.

Of course, if the car were here, I'd stick a different computer on it, put the fuel pump relay connection back to factory, and see. You don't have that option. After that, I'd start checking individual components.

Since you replaced the harness and the temp sensors, you've ruled out "incorrect temperature information" being the problem. This basically leaves the pressure switch (acceleration enrichment), the warm up regulator, the frequency valve, the frequency valve relay, the 02 sensor, and the computer. The most likely of these is the warm-up regulator, the least likely the acceleration enrichment switch.

I'm assuming that when hooked up correctly, your car runs well for say the first five minutes, and then starts running poorly. If I misunderstood, let me know. I suspect your car never comes out of warm up mode. You'll have to test each component for proper values. These components being the 02 sensor, the frequency valve, the warm-up regulator, etc.

You know, the more I think about it, the more I think the problem would be the frequency valve relay, or the warm-up regulator. Both provide a ground; both get signal from the fuel pump relay. But I could be way off...

Hope this helps,
Chris

thanks chris that is correct it runs right for about five minutes when relay is hooked up correctly then fuel pump relay gets real hot real fast.

You got a doozy here.
As I understand it, the jury rig does basically 2 things:
1) KILLS the FI relay by removing the ground on pin 31
2) runs the pumps via fuse 7 — toggle switch — double Y/R wires pulled from 87a

The result, if the above is correct will be power to the pumps, but NO POWER (from 87b) to:
A) the Lambda Relay, and thus the ECU, and Frequency Valve, plus O2 sensor is ignored
B) Warm Up Reg/Control Pressure Reg heater

This would mean running with no adaptive mixture control (no O2 sensor - F Valve).

The PO may (?) have got it to run like this (in a warm climate) by manual mixture adjustment, but that's just a wild guess.

But when you wire it back normal, with the relay operating and sending voltage out from 87b, you are again powering everything in A and B above, which seems to be conflicting with whatever the PO did to make it run withOUT the A and B stuff.

One more thing — you say "new harness". It's easy to mix up the plugs for the FV and WUR. When you restore normal relay operation, this would drive the FV full open (BLACK SMOKE). FV wire colors should be BN and GN, WUR/CPR wires are BL and SB.

Polarity on the WUR plug matters too. I think there have been posts where harness replacements have had problems here with blowing fuse 7, maybe it could also just cause high current? I don't remember the specifics right now.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

thanks bruce i will check the wire colors to the warm up regulator and the frequency valve tomorrow.

Mike, email anytime is fine. My hotmail just crapped out tonight. I can receive but not send. Will let you know when it's OK... Bruce
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.