91Jetta - no power

1991 Jetta (Mex) 1.8L auto digifant

I'm out of ideas....

Car was running fine, and still is except I found the car has no power when climbing hills -or- on the level, I push the accelerator pedal to the floor for passing gear and the tach just stays at 3k or whatever I was cruising at. Engine starts fine when cold (hr. in Pennsylvania temps in the morning have been abt 10 deg) and doesn't miss when running. When I push pedal for trans to shift to "passing gear" it does, but w/ no increase of engine speed - nothing happens.

When in park, idliing, engine winds-up easily to 4.5 - 5.5k -- seems like no problem w/ air flow.

Only a couple of months ago (about 5k miles) I put new air filter, checked vacuum lines, etc. Last summer (abt 8k miles) I installed new fuel filter and replaced pre-pump w/ new screen mesh filter (old one was maybe 120k on it). Air flow sensor flapper moves freely --

I've also checked air-duct-to-manifold for splits or cracks causing air leaks -- don't find anything.

Any ideas much appreciated !

Reply to
Jim Lacko
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Oh man here come the "made in mexico" comments...

sounds like the engine revs fine but the transmission is failing to kick down.

If the engine revs fine but the tranny is failing to downshift for aggressive acceleration, I'd focus on that.

I don't have an auto myself but the Bentley manuals troubleshooting says if kickdown fails to operate, accelerator cable is incorrectly adjusted.

In another section it says for poor acceleration/poor high speed performance, either the engine is out of tune (but you sound like you have the engine up to snuff), throttle cable incorrectly adjusted, or accelerator cable incorrectly adjusted (gee those last two sound the same...).

So I'd focus on the accelerator cable adjustment. This transmission I believe predates electronically-controlled transmissions like in the Mk3 Golfs/Jettas so the kickdown is probably mechanical.

The procedure for that is is too long to type. Get hold of a Bentley and check out what it says about it.

Reply to
Matt B.

He said it does shift down a gear, but there's still no power.

I'd guess the catalytic converted is done - car runs fine at low revs but just can't expell enough air at higher rpms. And the usual killer of cats is a dead O2 sensor causing it to run rich.

Reply to
John

Or his engine might have ECM grounding problems, or knock sensor problem, Air Flow Box, or Fuel Pressure Regulator problem, or ???

And I hope that you are not using mid-grade gas. I have found that sometimes running problems can come just from a bad batch of fuel.

What do the spark plug electrodes look like? Black maybe?

Reply to
One out of many daves

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