Lost drive with engine still running?

[R13]

What Happens?

• Car goes into in-gear decel
• Throttle does not add speed or slow deceleration
• With clutch in, car does not die, but idles smoothly
• CEL lamp comes on.

Twice the problem has corrected itself within a few seconds. Once I had to turn the ignition off and restart to fix.
On that note, turning engine off and back on does clear the CEL and fixes the problem.

When does this happen?

I've had this happen three times now:

• Once after a full-throttle squirt through 1st and part-way through second gear, it happened after shifting to 3rd and dialling back to half throttle.
• Once after a part-throttle acceleration (to, say ~5500 rpm) in 2nd.
• Once after just moderate (driving like a completely sane person) accelleration away from a stop sign (no more than 4krpm).

This is a '92, so mechanical throttle, no ECU mods, 243,8xx miles, only engine-related mods are headers, high-flow cats, and a tailpipe.

The first time it did this, the CEL code indicated a Fuel Pump issue, but as stated, the engine never dies entirely, and I never have issues starting it cold.

 

[britlude]

isn't the fuel pump a 2 speed/pressure affair, with extra pressure coming into play at higher revs? i think there's a fuel pump resistor, so there must be a relay to short it out somewhere..

just a thought, and guessing without getting the manual out...

 

[cmthomson]

I had very similar symptoms (abrupt loss of power for a second or so, then back to normal) at random times. It turned out to be the classic FI main relay solder crack issue, well documented here on Prime. I retouched the solder and the problem went away. Most here would instead recommend replacing the whole relay assembly.

 

[R13]

I had very similar symptoms (abrupt loss of power for a second or so, then back to normal) at random times. It turned out to be the classic FI main relay solder crack issue, well documented here on Prime. I retouched the solder and the problem went away. Most here would instead recommend replacing the whole relay assembly.

Well, I drive around with a spare in my glove box given how many instances of this I've read about. I was under the impression that the typical Main Relay failure led to full electrical loss as opposed to just motive power though?

 

[cmthomson]

It's the fuel injection main relay, so many functions are unaffected. In my case, I would lose engine power for a second or so while driving, then back to normal. Until one day it wouldn't start. YMMV.

Anyway, it's a fairly simple swap if you already have the part, and is likely overdue on a 92.