I recently did an engine rebuild on my 940. Everything ran smooth for a fairly short break in period (100 miles or so), and it never gave me any trouble starting. Then I went out of town for a few weeks. When I got home the car didn't want to start. It turns over, and even tries to fire. And if i stick with it long enough, it will finally run rough for just a second until I get the rpms up for a moment. After that it is all smooth, unless i let it idle for about 5 min, then it just cuts off quickly (no sputter). I'm thinking its a fuel issue, but i hear the pump run when i turn the key, and there is fuel at the fuel rail check valve... I didn't clean/replace the injectors during the rebuild, but there is seafoam in the tank. Flame trap is clean.
thanks in advance

 

when you've cranked it some and it hasn't started yet, pull a sparkplug or two, and inspect them... if they are wet and smell like gas, then you're probably not getting enough spark.

 

i've got fuel on the plugs, as well as spark (grounded plug). The issue is only during starting process. Once it starts (can take awhile), it runs rough for a few seconds then settles and purrrrs like she should.??

 

is this car LH2.4 or Regina? does it have EGR and/or Pulsair ? is it a turbo or not ?

I wonder if its not somehow getting a little flooded when you're trying to start it, but I'm not sure what failure mode might trigger that.

 

It is a non-turbo, as for LH2.4 or Regina, or EGR and/or Pulsair. I am not sure. I can find out if you tell me what i am looking for. If it helps, it is a stock 1995 940 B230F

update: the going has gotten worse. It now starts and does not want to idle but for a couple minutes. Also, when i now put it in gear it dies instantly. Heading out to clean plugs and check rotor/distributor.

 

well, a pulsair engine has this funny "E" shaped set of rubber tubes that go over the top of the head near the front, and deliver air into the exhaust manifolds. these pulsair engines are generally called B230FD ... they have one way valves in the pipes from the exhaust side, and when those fry, the tubes burn out, and all kinda weird running problems ensue.

pulse-air:

(the front of the engine is on the far right)

EGR systems have an EGR pipe from the exhaust manifold around the back of the block, and into the EGR valve under the intake manifold, and from there connecting into the intake manifold, this EGR valve is controlled by a EGR vacuum controller which sits just forward of the left strut tower, near the power steering reservoir, and looks like a little flying saucer with an electrical connector on the side/bottom, and two thin vacuum lines coming out of the side. one of those vacuum lines goes to the intake manifold vacuum tree, and the other vacuum line goes to the EGR valve. EGR is less likely to cause starting problems, so this probably doesn't matter.

B230F EGR:



a Bosch LH2.4 injection system has a conventional round ignition coil that looks like a beercan, while the Regina system has a square coil that looks more like a transformer. Bosch uses a 'mass air flow' sensor in the air path, while Regina has manifold pressure and intake air temperature sensors.

troubleshooting varies some between these two systems.

 

Wow thanks so much for the education, and clear explanation! I have both EGR and Pulsair systems, and it is the LH2.4 electronics.

No change from distrib. and plug cleaning. Still stuck...

THANKS!

 

look at that pulsair hose '8' and see if there's any sign of burning or cracked or crunchiness on the exhaust ends... the one way valves '7' die, then exhaust gasses quickly melt the pipe. you can plug it up below the valves '7', and have no deleterious effects. also plug up the air hose 9 if you do this.

otherwise, hmmm, hard to say what might be causing hard starting and bad cold idle. maybe the coolant temp sensor? that tells the ECU the engine is cold, so it injects more fuel. its a simple temperature resistor, and can be tested by measuring its resistance when hot and when cold and seeing if the values are reasonable. best place to measure it is at the ECU connector, the ECU is in the passenger footwell, behind the plastic panel on the inside of the right fender, just forward of the passenger door hinges. when you unplug the ECU connector, if you shine a flashlight inside the plug, you can see the pin numbers. get the car hot first before doing this. switch the car off, disconnect the ECU, measure the resistance ('ohms') from pin 13 to a handy ground like pin 5. measure it with the engine hot, then wait a couple hours til its cooled down to ambient and measure it again. see this table:

32F (0C)-- about 6000 ohms within a range of +/- 10%
68F(20C) -- about 2300 ohms
104F(40C) -- about 1300 ohms
140F(60C) -- about 600 ohms
176F(80C) -- about 300 ohms
212F -- about 190 ohms

the sensor is on the side of the head, under the intake manifolds, near intake port 3, it has two pins (one goes to ECU pin 13 as above, the otehr goes to the ICU ignition control unit).

 

hose '8' is very healthy, could something be up with part '10'. I will check the ECU once the sun shines again. Do you know which colored wire goes to the ECU and which to the ICU from the coolant sensor? Mine does not have a clip so I could have had the wires alternated, but like i said it has been starting and running fine.
Also I don't know if you saw my post that even after it has been running it won't go into gear or accept a load without cutting off. What I failed to mention is that by this point the engine was at operating temp. It will run if I keep the idle up or pump the throttle.

 

I don't know if this pertains to my current issue, but after putting the motor together, i had an oil leak from the rear main. SO i pulled the tranny and replaced the seal again thinking I may have rolled it on install. With the second new seal, it didn't leak upon start up, but days later began leaking again... could the oil trap be clogged, or could something else causing extra crankcase pressure? Could this affect start up?
Thanks

 

both halves of the ECT (engine coolant temp) sensor are the same, so it doesn't matter which side goes to the ECU or ICU, but the grey-white wire goes to the ECU, and the red-black wire goes to the ICU per my greenbook.

 

hmmm. i wonder if your timing belt jumped a tooth, or is somehow out of phase?

 

When you cold start the engine do you give her some accelerator or do you leave your foot off the pedal and just turn the key to start ?

I find with my Volvo that it does not like any pedal at all. (different model of course)
It will either start a little rough as if slightly flooded or may require 2-3 cranks to go.
My owner manual actually says also do not give it any pedal if cold starting.
I do this and she fires up first time immediately and consistently, summer or winter.

 

no fuel injected car I've ever had has needed any gas to start if it was in good tune.

 

I just wondered if perhaps volvonator2 was possibly giving his car some pedal with cold starts and getting a flooding issue?
One can sometimes do it unconsciously at times.

 

I feel like if timing jumped a tooth, then it wouldn't run as smooth as it does once it starts. It runs very smooth in neutral, but once i put it in drive it dies. The putting it in drive issue just started. Before my problem was only with starting, but now seems to have gotten worse.

I must have my foot on the throttle to get it to start. I even have to be pumping as it is trying to start... I suppose this could mean too much, or too little fuel. Maybe my pedal work is helping to get more air in the mix...

 

could the oil trap cause any starting issues?

 

I could not get the car to start today. It is cooler today than it has been 77 deg. vs 90 deg. I tested the ECT without ever starting the car and got readings from 607 to 1800's at air temp... I never got a constant reading and had to keep lifting the positive of my ohm meter on and off of pin 13 in order to get a reading. Is this normal? Any help is appreciated. I am getting stomped... I may retime the motor. But have not convinced myself due to it running fine yesterday after I eventually got it to start. Mistimed motors have never run fine in my book. arrrrrg!
Thanks

 

no, you definitely should have gotten a stable reading. your ohm meter is working correctly? touching the probes together should be 0 ohms or very close to it, and open, it should read overflow or something.

most DVM's autorange, and ohm meters often switch from k (1000 ohms) to M (millions) and back depending on what they see. at air temp, it should have been around 1500-2300 ohms, which might read as 1.50 K to 2.30 K ohms depending on your meter.

 

a clogged up oil trap would just cause seal failure, and oil leaks, it wouldn't stop it from running.