In post 20, do you mean it starts a little bit? Does it try to start?

 

I turn the key, it cranks, but never engages and stayes running

 

pm'd you

 

OK... Had someone come over and help. We were able to get it started, but only temporarily. The engine will start, but after a few seconds it will flood and stall. We would pull the plugs, burn off the fuel with a torch, turn over the engine to empty the cylinder and start over again. We tried with the o2 sensor, maf, plugged and unplugged. We also jumped the coolant sensor plug with a paperclip so it would think it was hot. So we're getting fuel and spark, but too much fuel to keep it running. Any thoughts on that?

 

Check your fuel pressure regulator. It sits at the front of the fuel rail. Pull the vacuum hose off of it and see if there is fuel getting into the vacuum line. If fuel drips out then the FPR is shot.

If that isn't the case, I'd check for leaking injectors.

 

The vacuum line is dry. The airhose going from the maf to the throttle body however had a lot of fuel in it.

 

disconnect the cold start injector, see if it starts.

 

Same person is coming over tonight to check a couple other things. We'll try that. Where is that injector located

 

cold start injector goes into the top of the intake manifold, pointing at the throttle body.

it SHOULD only spray once for about a second when the engine is /really/ cold...

hmm, I just double checked, and my 1987 240 doesn't have one (and 1988 is identical to 1987). that kind of rules that out.

ok, forget cold start injector. time for a fuel pressure test. this will require a fuel pressure gauge WITH a volvo specific hose T adapter which you put between the fuel line and the fuel injector rail... I believe 87/88 240, the fuel pressure should be 36-38 PSI when the vacuum line is disconnected from the fuel pressure regulator (later LH2.4 cars were 42-44 PSI)

 

They are going to check that the injection system isn't shorting or grounding out keeping the injectors on all the time. Engine will start but "flood" out. When we remove the plugs they are so soaked with fuel we have to shake out the extra fuel before we burn them off with a torch

 

all 4 injectors are wired in parallel. Power is on the yellow-red wire, which comes from the fuel pump relay pin 87/2, and they are switched to ground on the green-white wire which comes from ECU pin 13 (normally floats high, but is 'grounded' to fire the injectors).

 

Thanks. I'll relay that information if he needs it. He's a mechanic so he's got more knowledge than I do

 

OK, so now he put a noid light on injector 1. Cranked it over and it was blinking so fast it almost looked like a solid light. I found the relay under the dash by the ECU checked for corrosion, burns etc... Could the relay be in an "open " position causing the light to flash so rapidly?

 

that relay, behind hte glovebox, is a dual relay, one half powers the ECU and most of the rest of the fuel injection system, and the other half powers the fuel pumps.

the injectors should fire twice per full turn of the engine.

1988 has LH 2.2, this system gets its timing from a hall effect sensor in the distributor... the hall sensor is connected to the ICU (which on an 88 240 is on the right fender just behind the headlight), and the ICU sends a cleaned up version of the timing signal to the ECU, which is mounted on the right side of the right front seat foot well, just forward of the lower door hinge. the ECU uses the timing pulse and assorted other information to decide how long the injector pulse should be, and fires the injectors.

 

ok. I traced the wiring harness from the injectors across the firewall and into the cab on the passenger side to a white 6 pin box that then goes to the ECU bolted to the side of the car. Is that the relay you speak of? Could that be a culprit

 

if you think the injectors are firing too fast, I'd hook a timing light up to the coil, and leave the noid light plugged in, and crank the engine. they should fire at the same rate.

if the engine coolant sensor tells the car that the engine is really really cold it runs way too rich, this could conceivably flood the engine. high resistance like 10K ohms is sub-freezing cold. 3000 ohms is 'room temperature', 200 ohms is 'hot engine' (boiling)

if the fuel pressure is too high from a failed fuel pressure regulator, the injectors would spray too much gas.



that relay powers the fuel pumps and the ECU, which yeah, is on the right side of the right footwell.

the timing signal comes in to the ECU on pin 1 (from the ICU).

For a engine wiring diagram, see page 19 of this PDF:
http://www.ohio.edu/People/ridgely/V...87.pdf#page=19

that shows the ICU and ECU and how everything is wired to them. "lambda sond" on the right is the O2 sensor. "main relay" is the probably-white one behind the glovebox. "breaker" is the throttle position switch (signals idle and full throttle).

if the main relay is bad, the fuel pumps don't work. since you are flooding, we know they are working. for completeness: the fuel pumps are inexplicably not drawn on this diagram, but they are connected to either side of fuse 4 as shown on the next page #20, that in turn is connected to the same yellow-red power that runs the injectors.

the 'Chrysler' ICU's used on 198?-1988 240's have a somewhat funky main electrical connector. you have to be quite careful with that plug, and not rock it when plugging, unplugging.

 

Ok. the noid light was blinking fast enough that I could not count the blinks. Is that too fast, Are we talking a couple times a second. Would testing the fuel pressure on the rail rule out the pressure regulator or is that a replace to test scenario. Can the ECU and ICU be tested? I don't want to get to the replace 1 thing at a time until my bank account is empty or the problem is remedied. in an effort to keep the engine running we jumped the plug for the coolant sensor with a paperclip to simulate a "hot" scenario. No difference was made. Would you tend to lean towards excessive fuel pressure. My plugs and the intake line going between the intake and the MAF sensor was filled with ALOT of fuel. Im sorry to be asking stupid or redundant questions, I'm just limited in my knowledge

 

idling at 600rpm, thats 10 turns/second, the fuel injectors will fire twice per turn so 20 flash/second. cranking speed is slower than that, but still faster than you can count.

if the fuel pressure at the rail is fine, then the fuel pressure regulator is working.

 

OK, I checked the fuel pressure tonight. I was told it was correct. Going to get another ECU. Found one on eBay for 40 bucks. Let you know how it turns out.

 

ok, the saga continues..... I purchased an ECU today. Installed it and my friend came back over and we torched the spark plugs and emptied the cylinders of extra fuel. It started... but after about 5 minutes (while holding my foot on the accelerator) it started missing and died. Pulled the plugs and they were soaking wet again. Now what.... I'm clueless.