1994 Chevy Lumina APV Problems

[jeslookn]

Hi Everyone,

I have a 1994 Chevy Lumina Van LS with a 3.8 Liter Engine with 170,00 miles. Here are the problems I have been having with it.

1. As the weather has become colder in the morning when I started it up, the Check Engine Light would come on, the engine would run for a few seconds and then die. It seemed like the colder it got, the more times I had to try to start it until it would start up with the check engine light off. Once the van was warmed up I could go to the store and it would start right up as long as the engine was still warm. Finally, one morning I drained my battery and I couldn't drive the van that day. I don't have a battery charger so I used a 10 amp power supply and a one ohm resistor to charge the battery. I monitored the current going to the battery and the voltage across the terminals. With 1.12 Amps being delivered to the battery the voltage at the terminals was 15.5 volts. I knew the battery was bad. The next morning I put the battery back in the van and it took 10 tries to get it started before the check engine light was off. I drove to Autozone and bought a good battery. After replacing the battery it didn't matter how cold it was, the check engine light would come on once and then the next time I tried, the engine would start without it coming on.

2. While driving the van, sometimes it hesitates when I press on the gas, and sometimes while just cruising (not accelerating or decelerating) the engine rpm increases ( don't have a tach, but hear it) and the speedometer increases by around 10 mph. There is no telling when this happens. Sometimes it happens multiple times for a period of a minute and then is fine. It is intermittent, but seems to happen once the engine has warmed up. I can be going 30 mph or 60 mph when it happens. Someone suggested that my lockout torque converter could be bad. I searched on the INTERNET and found a test where you drive the vehicle above 50 (not accelerating or decelerating) mph and press on the brake to see if there is a subtle downshift and release the brake and wait for a subtle up shift. I felt the downshift and up shift, but the up shift is much harder to feel or hear. Sometimes I can't tell.

3. I had mechanic use a snap-on scanner and he came up with two codes.

351 EST: Electronic Spark Timing not toggling.

650 Quad something (I couldn't read what it said and don't remember what he said). The mechanic said it was a body code and had something to do with a transmission module under the dash. I looked under the dash on the passenger side and didn't find anything.

My van is in between OBD-1 and OBD-2. It has a twelve pin connector but the B terminal is missing so I can't short pins A and B together to make the Check Engine Light flash. I have talked to other people and I don't know if I should have OBD-1 codes (two digit) or OBD-2 codes (P plus 4 digits) Does Snap-On have their own codes?

The mechanic said my crankshaft sensor was bad and could be causing the problem with the transmission module and I let him replace it. When I picked up the van, the check engine light came on the first time I tried to start it and the van ran the same as before. He rescanned the van and the same two codes came up. I have since quit ties with this mechanic. I'll be damned if I'm going to pay someone money to replace parts that are not bad by using the shotgun method.

4. I then removed all the grounds that I could find in the engine compartment including the heavy Gage wire going from the battery to the engine block, cleaned the terminals, the bolt, and the place where the terminal contacted the body and reinstalled them using dielectric grease. Since then, the check engine light has not come when I start the van.

Questions:

2. Does anyone have an idea what could be wrong? I am really hoping and praying that my transmission is not slipping.

3. Are there any tests I can perform to rule out transmission slippage?

Thanks,

Jesookn

[plambeth]

I don't have the answers - but am interested too - having some transmission slippage too.

FWIW - sometimes the engine codes don't reset until you either disconnect the battery, or have a certain number of ignition/starts. So if the mechanic never disconnected the battery after he performed the service, it is possible that they were fixed. There again, guess the dude should have done that.

[russpaulson]

First, thanks to jeslookn, I will try to clean my ground cables to get the check engine light off on my '94 Lumina Van APV.
It would idle fast and then so low it shut off. I read online that a new computer would rectify that, AND IT DID! (located in right wall after taking out the compartment, $130 from Advanced Automotive, and they will install the chip from your old one into the new one)
It now runs great, but the Check Engine Light won't go off, even if I disconnect the battery, etc. So, I'll work on the ground wires next.


Secondly, I was told by a mechanic that the fifth gear shifts electronically in an automatic transmission. The electronic module is just inside a small cover on the transmission case. Hard to get at. Worth a try to replace it.

Russ Paulson

[LMP]

Originally Posted by russpaulson

... the fifth gear shifts electronically in an automatic transmission. The electronic module is just inside a small cover on the transmission case....

..well maybe it would be interesting to specify what is intended here...is there a problem ?

In fact there is no 5th gear in this transmisison..just 4.....however, when the TCC (torque converter clutch) applies, it can feel like an extra gear because it causes a drop in the RPM as the converter slip goes down to zero once the clutch is engaged.
ANd all the control electronics in this model in within the ECM....do not search the transmission.
With more precise details of your problem..if any...more help may be available. The CEL can be tripped by many factors. Unhappily, the '94 is the exception as the codes cannot be flashed from the CEL nor read by "normal" codes readers. SO...if no adverse symptoms can be precisely described, it is try and test....unless you can live with the CEL....

[Tech II]

Russ, like LMP said, a lot of misinformation here...