hey guys need some help with this i ran my car for trouble codes and pulled these. just a few of the many

54. Low voltage at fuel pump OR
Low voltage at Fuel pump relay OR
Output failure at quad driver module


41. Fault at cam sensor OR
Cylinder select error OR
Tach input error

34. Low voltage (high vacuum) at mass air flow sensor (or MAP sensor

can some one tell me what to do about it

thanks

 

Phlucking computer!

 

34. Check your relay next to the sensor before you do anything else. Less than $10, if the prob don't go away it's one less thing to worry about. Also check your wiring to and from the MAF.

41. Can't really tell you much here. Don't know about the cam sensor. You can check the wiring on the ignition coil for problems and the wiring inside (for the tach) for problems also. You may also have a bad PROM (chip) in the ECM causing this... I've read that a cyl select error can be caused by either an unseated or defective or incorrect altogether PROM.

54. This can be a pain. When you go to the parts store for the MAF relay, you need to ask them for TWO fuel pump relays, one for the code 34 and one for this code (they are identical.. thats how I fixed my probs). You can also get a nice long set of jumper wires and connect the positive to term G (or whatever the lower left hand terminal is labeled as) and the upper right one (Term A) of the ALDL. If you can hear the pump running when you connect the battery to the lower left hand terminal and ground (terminal A) your wiring, relay, and fuel pump are good and the ECM ain't. I ended up replacing my ECM.... (Cash register sound)

 

the fuel pump runs when i turn ignition to on but after about a min with out starting it becomes a higher pitch the engine during idol seems to lope (highs and lows) almost like its missing but its got new plugs and wires as well as cap and rotor this all started when my brother riped the emmisions system out emmisions tubes out of exhaust manifold are pinched (kinked) closed any advice on weather that could be a prob and if so how to fix it

 

I get the code 54 also, haven't figured it out yet though. Car seems to run fine. I do get the loping when at idle also. Maybe it's a V-6 thing?

Can any tell me why after a relativly short drive, say 1/2 hour or so, if I turn the car off it won't restart for several hours. Seems as though the fuel pump doesn't want to come on. I've replaced the relay... no change. I've tried jumping the ALDL, think it's port G to power and the pump comes on fine.

Any body that has any sensible suggestions, thanks for the help.

 

You might have a problem with the fuel pump driver in the ECM. See if you can borrow a ECM and test it

 

I would think a problem with the fuel pump driver would be constant ?
I was thinking maybe the problem lies in the wiring harness, maybe getting affected by heat ?
I replaced the ECM a few months ago, could it be something in the chip ?

 

Trouble code definitions for our engine:

http://www.troublecodes.net/GM/86-89_28S_mfi.shtml

34. MAF sensor signal showed air flow to be less than 2 gm/sec or the MAF circuit was shorted.

41. The number of crank reference pulses did not match the number according to the PROM when engine speed was under 2000 RPM, or the incorrect PROM has been installed.

54. Fuel pump signal voltage was less than 2 volts for 1.5 seconds.

 

Check the relay connector for broken/frayed wiring. The connector can be bought at a parts store, but it is NOT cheap (try about $25!).

If the pump runs when you jump terms A and G of the ALDL with a power source, look at the ECM for problems. If you like, I can sell (or give you if you like.. PM me) you a 2.8 PROM that was installed in the ECM I am now using (you're supposed to keep the original PROM).

However, I would look at the oil pressure switch also since your problem seems to not just lie in the fuel pump relay circuit. The switch cuts power to the fuel pump whenever the oil pressure becomes 0 or almost 0 PSI. This is located by the oil filter and has TWO terminals, a black and orange wire (thats what mine are anyways, unless your car has the newer version which is a 3-wire unit). This can be affected by heat since it is in such close proximity to the exhaust manifolds, so check the wiring there too.

 

I checked the lower wires near the oil filter, they seem fine. The wires at the relay are anorher story, pretty much frazzeled. Looks like someone gave them a couple of good hard yanks.

Would it be easier to get a connector from the bone yard and splice it in ? I'm there's enough wire to cut and re-terminate to a new connector.

 

You COULD in theory do that, but as I've seen, most of the junkyard cars I know of either don't seem to have much in the way of their electronics left or the stuff they do have is in bad shape similar to what you have there.

If you do find a good one, I could use the A/C compressor relay connector (mostly green wiring) because mine is in the same shape as the F/P relay connector was.. that one is even more expensive than the connector for the F/P relay...