have a 90 model 740 b230f.

upon exceleration engine skips and sometimes worse.

have performed full tune up.

what should i do now?

 

define "full tune up." What all did you replace?

 

There are so many things that can cause engine skip. Since you did a full tune-up, did you also check the spark plug wires? (Put a timing light pick up over each wire and look for light.) Other possibilities include the RPM sensor, fuel injection relay, radio suppression relay, and faulty (bare) wiring somewhere.

 

full tune up included wires, plugs, cap, and rotor. also replaced weak coil yesterday.

 

more specifically, engine idles fine, but skips bad under exceleration. sometimes a backfire.

also more recent repairs include timing belt, water pump, and exhaust system.

 

LIke it breaks up as you accelerate? At any specific RPM?

 

breaks up at lower rpm

 

my 90 740 did the same, replaced the pressure regulator cleared up. easy to replace.

 

Recheck valve/ ignition timing too.

Regards, Andrew.

 

where is the presure regulator?

 

Anyway you can access another ECU?

 

replaced fuel filter yesterday. cured most of the problem. now engine is flat just after it shifts into over drive.

thanks for the help getting to this point. now what?

 

Plugs, leads, cap and rotor. Give the computer a week or so to relearn, they are a fairly adaptive system.
When things go bad, the ECU will skew settings quite a bit trying to get the engine back to where it should be. It assumes everything will be the same after things are fixed till it starts seeing consistently different readings from sensors etc.

Regards, Andrew.

 

i will give it a few days, however, it is back to running sick again.

thanks

 

If the car ran fine before the tune up, and is missfiring after, then a component you changed, or installed incorrectly, is causing the problem. Retrace your steps, may be even put back the old parts. You may have a factory deffective part.

 

LH2.4 learns in one day, if that. Thats according to run in guides in the green books. So i'll have to take their word on it. But I ask again.

Do you have the ability to access another ECU???

 

1-Did the engine have these problems before the tune up?
2-Is the engine making boost?
3-Have you checked fuel pressure?
4-As adub96 asked...Do you have access to another ecu?



Dan

 

thanks everyone. alot of help.

engine ran fine after tune up. broke timing belt and then replaced. am sure the timing marks are on spot. ran fine for a day after fuel filter replace, then went back to running sick. fuel filter was cloged. will check fuel pressure.

do not have access to another ecu.

thanks again

 

Pull codes. If it is running that badly it WILL be setting a code.

Regards, Andrew.

 

If the fuel filter was clogged do you think that the check valve thats in the fuel line is also clogged too?
Maybe even the presure regulator is getting blocked up.

Run the tank down to almost empty alot?

(just thinking out loud here)