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Crazy Bucking in 1st and 2nd (89' 245)

Nothing looks bad under the dash, wires are in good shape. I am curious about these wires that are cut and the plug but it ran fine without them before. If anyone knows what they are for though I would love to hear it. I also have a plug that has been jumped on the passenger side near the ecu. I have been curious what that is but have never touched it
 

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Plug under the dash didn't post in last message. I tried to add a photo of the jumped plug but it keeps saying it's too bit for some reason
 

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JonLasaga said:
Random question: where would this wire go? Comes through the firewall at the throttle pedal, related possibly?
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The green wire should not be plugged into the IACV, The IACV needs to have a Bosch type connector, that is crazy, the green wire looks like the AC switch wire( I don't see how that connector would fit on there ).

Locate the IACV Bosch type connector(black and square shape) and plug into the IACV( it should be right around that area/ under the intake )
 
Otto Mattik said:
The green wire should not be plugged into the IACV, The IACV needs to have a Bosch type connector, that is crazy, the green wire looks like the AC switch wire( I don't see how that connector would fit on there ).

Locate the IACV Bosch type connector(black and square shape) and plug into the IACV( it should be right around that area/ under the intake )
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Oh yeah it does kinda look like it's plugged in to the IACV but it's just resting there in the photo it's not plugged into anything. The whole ac system is unplugged so good to know If I ever get around to fixing the ac. The IACV is plugged in properly in the back. Thanks for the heads up though!
 
Took me a while to get my new hood hinge into adjustment. Just now getting back to troubleshooting full time after work. Here is all I have found so far today:

Found the fuel pump relay (?) In the trunk had a loose ground wire. Tightened it, no major change. At some point car started pulling in 1st fine full throttle but 2nd still bucks at lower rpm at anything more than 1/8th. At high rpm is clears up

Hooked up a timing light again and reved it. It was retarding at higher rpm free revving. Not sure If this is normal, ignition is still suspect. (Timing at 10 degrees at idle)

Car pulls fine in all other gears all throttle ranges.

Gonna check the TPS with a multimeter tonight might be my last job for today before it gets too dark. I got a fuel guage as well that I can put in the cabin to see If there is variation in pressure under load. Issue only seems to happen under high load low rpm

Thanks for all your help so far everyone I'll continue to post if I figure something out!
 

JonLasaga said:
Oh yeah it does kinda look like it's plugged in to the IACV but it's just resting there in the photo it's not plugged into anything. The whole ac system is unplugged so good to know If I ever get around to fixing the ac. The IACV is plugged in properly in the back. Thanks for the heads up though!
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Ok, was not sure what was going on in the photo.
 
Small update, I actually can induce this issue now with no load just free reving. I couldn't get contact on the tps tonight to check if that is the issue but I think fuel pressure or ignition must be the issue now.

Engine does stumble and flash CEL at certain revs when I free Rev around the same 1/8 to 1/4 throttle
 
Small update but no fix so far:

I found a parts car to pull some stuff from. Tested TPS and found that it wasnt reading in some ranges. I managed to replace the TPS. this changed almost nothing besides fixing the stumbling when reving the car. I went through more of the wiring and found some spider eggs in some connectors for the ignition wiring and cleaned that out but no change. I am tempted to say the ICM might be suspect but im still trying to figure out how to test it. Any additional advice would be much appreciated. I am pretty stumped by this issue so far but continuing to work on it.
 
Have you checked for any codes on the ignition? That is socket 6 on the diagnostic plug. Also there is a diagnostic mode for the fuel injection. It tests sensors and the throttle position switch among other tests.
 
Hi. I had a very similar problem that I battled on my '87 240 for years. Ultimately turned out to be an electrical problem. Which sort of makes sense, if the electrical connection isn't quite connecting it'll arc a few times and you'll get intermittent power. Check your grounds, hit everything with contact cleaner, sand down any painted surfaces there's a ground connection landed.

You mentioned almost running out of gas - if the tank sat empty and unsealed in the junkyard for a while is it possible that debris got in, and when the fuel got low the pump sucked up the debris at the bottom? If you can, maybe throw a new fuel filter at it again, if it doesn't fix it then you have a spare for later.
 
dl242gt said:
Have you checked for any codes on the ignition? That is socket 6 on the diagnostic plug. Also there is a diagnostic mode for the fuel injection. It tests sensors and the throttle position switch among other tests.
Click to expand...

Engine and OBD Diagnostic Codes<

Volvo Engine and OBD Diagnostic Codes<
www.volvoclub.org.uk

Actually just did this right now! Thanks for the advice I got: 2-3-1 which says I'm running lean with a possible pump or sensor issue. (Socket 6 test 3).

Is this the oxygen sensor it would be referring to?

I did some destructive testing (bouncing it off the limiter and clutch dropping till I got a code) sorry volvo :sad:

All ignition codes were clear but in the test mode I did not hear the in tank pump running. IAC and injectors did run and sounded good. I'll try replacing the in tank pump since I have a spare. Otherwise o2 sensor? Or is this another sensor?
 
volvo_cowgirl said:
Hi. I had a very similar problem that I battled on my '87 240 for years. Ultimately turned out to be an electrical problem. Which sort of makes sense, if the electrical connection isn't quite connecting it'll arc a few times and you'll get intermittent power. Check your grounds, hit everything with contact cleaner, sand down any painted surfaces there's a ground connection landed.

You mentioned almost running out of gas - if the tank sat empty and unsealed in the junkyard for a while is it possible that debris got in, and when the fuel got low the pump sucked up the debris at the bottom? If you can, maybe throw a new fuel filter at it again, if it doesn't fix it then you have a spare for later.
Click to expand...
Electrical is possibly an issue. Im still going through everything related on the harness and all of the grounds but there is quite alot to look for. I did check the fuel filter recently. I had to replace the hose that goes from the filter to the pump about a month ago and the fuel that came out of the filter was very clean. taking samples from the tank before the inline pump also shows the fuel is clean. I think the tank is in relatively good condition. thank you for your input!
 
If you have a multimeter with a 15 or 20 amp test mode. Then you can replace the intank pump fuse 4 with the meter and see if the pump is running when the engine is running. Or you can also run only the pump engine off by jumpering from fuse 6 to fuse 4 on the right side of fuse 4 with the fuse removed. You can also use your meter for this jumper and test the pump current that way.
 
dl242gt said:
If you have a multimeter with a 15 or 20 amp test mode. Then you can replace the intank pump fuse 4 with the meter and see if the pump is running when the engine is running. Or you can also run only the pump engine off by jumpering from fuse 6 to fuse 4 on the right side of fuse 4 with the fuse removed. You can also use your meter for this jumper and test the pump current that way.
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I gave this a shot and it looks like the in tank fuel pump is running as well as the inline pump (as long as I'm not just running the inline pump on both sides when I jump it)

What else could be suspected from the code that I got? I tried resetting the code and it is still there. Made sure the grounds for both pumps were solid
 
I'm sorry if I am saying things that have already been checked, But no damage to the MAF or intake Leaks? That is truly what that code could be from, check to make sure the coil in the maf is not damaged, as that can cause it to be lean.
 
The only other thing that could be going on with the intank pump is the feed hose from pump to the outlet pipe can decay and let fuel leak back into the tank.

The code could be from something like less fuel from a leaking into the tank pump. If it's better when the tank is full that is a symptom of this issue.
 
dl242gt said:
The only other thing that could be going on with the intank pump is the feed hose from pump to the outlet pipe can decay and let fuel leak back into the tank.

The code could be from something like less fuel from a leaking into the tank pump. If it's better when the tank is full that is a symptom of this issue.
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Thanks for all the advice I may as well check that hose. Redid my sensor tests and all seems well. I did have a code for tps but it tested fine its possibly out of adjustment. I'll check on that as well.

Any chance my 02 sensor could be throwing this code?
 
It's possible but usually the 02 sensor throws it's own code. I would put the voltmeter on a fully warmed up engine and check the sensor signal. Make sure the switching is as fast as slightly less than a second per change. If it's slower than every second it's a worn sensor getting slow to react.
 
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