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240 won't rev past 1500rpm

S

SoDakVolvo

Member
Joined
Sep 22, 2012
Location
Sioux Falls, SD
I have a 1991 240 that starts fine, idles fine, then won't rev up past 1500rpm. Ive replaced the plugs, cap, rotor, crank position sensor, fuel pump, fuel filter, fuel pump relay, fuel pressure regulator, fuses, intake/tb gaskets, air filter, flame trap. I've also tested known good mass air flow sensor and idle air control vavle and cleaned the intake manifold and tb. What are my other options? Ive seen something about the o2 sensor causing issues, or could it be the coil,powerstage,plug wires something stupid like that? And yes ive used the search function: http://www.volvo-forums.com/t39071-1991-940-gle-won39t-rev-past-1500rpm.htm http://www.turbobricks.com/forums/showthread.php?p=4063139 and nobody had any cures there either. So any help is appreciated before I just give up and junk it haha.
 
andysbeta said:
Try another fuel ECU.

I bought a 1990 240 for $200 because it wouldn't go above 1,500 RPM. Just would shut down. The owner was frustrated with it, guess it was intermittent then it just failed in that mode. The fuel ECU was defective. Replacement cured that problem .
Click to expand...

+2 on new fuel computer. Mine did this because I blew up the ECU by crossing the IAC and FPR wires.
 
SoDakVolvo said:
So I looked this up http://volvoforums.com/forum/volvo-240-740-940-12/240-keeps-blowing-ecus-please-help-67857/ and it sounds like that could be my issue. Last fall my return pipe on the waterpump blew the seal and dumped all the coolant straight onto the alternator and everything below the waterpump so that could have been the culprit. Also can I test my fuel ecu out of my 940 turbo in my 240 just to see if thats the problem or won't that work?
Click to expand...

NA and turbo computers are not interchangeable.

Check out my thread for a similar problem. It started out as a high idle when I had the wires crossed, but once I corrected that issue, a problem nearly identical to what you're describing occurred.

http://forums.turbobricks.com/showthread.php?t=291730
 
You can substitute the turbo ECU but it will run like **** until it goes into closed loop operation - the turbo ECU will indeed adjust itself to run in the NA car . I've done that in a pinch, the 940 turbo has extra pins for the E-Fan but the 240 omits the e-fan circuit so there would be no worries aout frying the ECU.

I bought another failed 1989 244 car for my great grandpa a few years back, I had no spare NA ECU's, but a turbo one. I just put the turbo one in, and it ran like dog****e until the o2 sensor came online then it trimmed and dialed itself in and actually ran quite good by the time I got it back home 20 miles away.
 
I had a Saab with LH that did something similar and it was a bad ECU. It acted like the rev limiter was at 1,200 RPM.
 
Another possibility is a plugged cat. I melted down the cat in my old VR6 Jetta one time (rain storm shorted one or two cylinders, I had it on cruise control and didn't notice that it was floored to maintain speed, raw gas dumped into the cat). The symptoms were that it would run perfectly fine at idle, and at lower rpms, but either in gear or in neutral, it would run into a brick wall at ~2000 rpm.
 
'85 244 won't go above 1800-1900 RPM

Please help! My '85 244 4-speed/OD (with 134k miles) will not go above about 1800-1900 RPM. Was driving home today and had to limp back, shifting by 1800 RPM. Did smell a little burned rubber/plastic at the beginning. Is this the ECU? If so, can I grab an ECU from any junkyard 240, or does it have to be from certain years?

Thank you!

'85 244 4-speed O/D
'86 244 4-speed auto
 
Wont rev can mean severely retarded ignition timing. Computer controls timing on your car, but maybe the belt jumped. Pop the cap off the dist, set timing to #1 TDC, and see if rotor is pointing directly at the notch in dist base.

Or clogged exhaust MAYBE. Put a vac guage on the intake manifold and do research on what the readings would be with clogged exhaust.
 
ZVOLV said:
...Computer controls timing on your car...
Click to expand...

This thread has a new topic beginning in post 10, so that has perhaps confused you. You're correct the computer in this car does indeed control the timing, but the distributor provides the reference from which it is adjusted. It's question was answered in post 11.

The subject of post #10 is a car with Volvo/Chrysler (VC) ignition, often referred to by the Fuel System LH2.2 it is paired with. Dizzy uses a Hall effect sensor to time the spark.

I bet you were thinking EZK-116 with the Crank Position Sensor based on the OP's car. :-D
 
Yep. Fugging threadjackers!!!


In my experience, if the engine wont rev, it is because the ignition timing is uber retarded. Happened to me recently on a 1986 GMC Jimmy V6 and also on a 1993 Ford 5.0L V8. Both were torn apart heavily and put back together by various hands and they wouldn't rev at some point during reassembly and the solution was ignition timing.
 
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