Gen 1 with Roe blower misfiring???

[RedEnuf93]

I really havent had much problems with my car, but this one puzzles me a bit...

I have Roe blower, VEC 2 and 8 lbs pulley and have driven about 2000 miles since the installation. About 2 weeks ago the car started to spit (misfire) lightly.
I pulled the plugs and they were the cleanest plugs that I have ever seen. All 10 of them. I was not even able to tell a difference between #10 and others. I changed them anyway (Bosch plugs from Roe)

Last week it was idling up and down when cold and calmed down when hot. It idles close to normally, but if I try to move it in the garage, I get hesitation and possibly backfiring.

I drove it few miles and when I am holding 2000RPM it drives normally, but with a light misfire. If I try to accelerate it misfires badly.

Innovative wideband gauge is allover during the misfires, up to 30 and down to 10.

I replaced the TPS and MAP, no help. The RPM gauge needle drops in a weird way, in a jerhy manner, maybe not related to problem?

It has not thrown any codes. Stored codes were 12 (battery disconnect) and 33 (A/C relay problem, which I dont use anyway..). Car is a 1993 model.

So, what next?? Bad battery? Coil packs????

Red

 

[Mccarlin]

Hmm, you check the IAT sensor yet? since you replaced the other obvious like TPS and MAP already.
How old are the plug wires?

 

[RedEnuf93]

New MDS 8,5mm wires. Car drove and worked fine with all added mods for 2K miles.

By the way, when stomping the accelerator heavily, I am not talking about small misfiring, it is MASSIVE!! Kind of like a handgrenade....

The new plugs are now black only after few miles (maybe 10?), with tip being white.

 

[Schulmann]

I don't know very well GenI vipers but in the case of a real missfire the PCM should through a code on GenII

My first thought was also the TPS.
When the TPS is poorly adjusted the PCM advances the ignition and it causes an idle swing.

I would forget the battery and coils for the moment.

I would try to adjust the throttle bodies but be carefull with the reading of the TPS. Once I had a similar issue and by adjusting the throttle bodies I elliminated the issue.

Also double check the VEC2 program. I know that certain programs for the 8lb pulley are agressive and tend to alter the ingition very early in the vacuum.

You can also ask Sean for an advise.

 

[Dave R]

Have you tried to reload your VEC2 mapping?

I have a 94 Gen1 with a VEC2 and have had the same problem periodically over the past 2 years. For some reason ??? the VEC looses its mapping. I just reload with the card and all is well!

 

[RedEnuf93]

Have you tried to reload your VEC2 mapping?

I have a 94 Gen1 with a VEC2 and have had the same problem periodically over the past 2 years. For some reason ??? the VEC looses its mapping. I just reload with the card and all is well!

I had smaller issues with VEC2 and the reloading helped. With this problem I have done it 3 separate times and no help....

 

[Dave R]

May want to check crank sensor. Both timing and tach are based on the crank sensor. Try moving the sensor wires and see if it has an effect.

 

[ArlyDude]

Sounds like mine when I had my O2 sensor problem. Sometimes I would get an engine light, sometimes I wouldn't. Whatever you do, don't use BOSCH O2 sensors!

 

[dansauto]

Arly his is a gen 1, differant type of O2 sensors. I dont think its the crank sensor, That would throw a code. I am thinking Vec 2 or coils.

 

[KenH]

Try wiggling your crank position sensor tap for the VEC2 while the car is idling and see if it misses. I had an intermittent connection there and the car would cut out randomly especially when accelerating hard. Probably because the wires would see some stress. If that doesn't show anything, I'd wiggle all the VEC2 connections to make sure you don't have a bad connection somewhere.

 

[Casey]

Fuel Injector connectors?

 

[IEATVETS]

Strange, I have a Paxton and I had the exact same problems after I drove mine about 500 miles Lauri! Mine started to happen as the temperature was getting cooler. Mine ended up being fuel related. Was dumping WAY to much fuel so they took a bunch of fuel out and problem was solved. Granted we have 2 very different systems but can you get a A/F reading to see where you are at?

 

[RedEnuf93]

I have fuc*ing fixed the problem....


I wondered why the starter was turning a bit slower and gauges acting funny. Then I remembered an old post about GEN 1 acting silly with "almost dead" battery.


It turned out to be a DEAD BATTERY!

Car runs like a ***** monkey again, especially in this 30 degree weather!!