Diagnosis - cut out at cruising speed - late 1.6 XU

[danj.pdx 3]

Hello all,

 

Has anyone dealt with similar symptoms to this? This is a '92 1.6 GTi on the west coast of the US. 

 

At part throttle cruising speed, around 3k to 3.5k RPM, the motor will very briefly (like 1 second) cut out, then keep running as normal. At the same time, the tach jumps a few hundred revs, then goes back to normal. This only happens when the car is warmed up and has been cruising for a few minutes.  This happens randomly, sometimes every few minutes, sometimes a couple times w/in a minute. There doesn't seem to be a pattern.

 

This used to happen with less than 1/2 tank of fuel. It's now happening regularly. Give it some throttle and it picks up just fine. Besides this cruising throttle issue, it runs great.

 

It has a new fuel pump & filter, coolant sensor, tune up parts (belts, filters, plugs, cap, rotor, etc), tachy relay.

 

Have any of you experienced this, is it common? Any suggestions?

 

Cheers!

Dan.

[Tom Fenton 1,524]

Yes I've had this, it was a duff air flow meter for me.

[DamirGTI 323]

Ignition module ..

 

D

[danj.pdx 3]

Thanks Damir and Tom. 

I have replaced the Ignition module, so maybe the airflow meter. I'll clean it before replacing. Likely not an inexpensive part to source.

 

Cheers,

Dan.

[Thijs_Rallye 86 4 Cars]

A jumping tacho would indicate a failure in the ignition leads to me. I've had this twice before, one lead had a intermittent connection. A new set of ignition leads fixed it for me.

 

AFM considering age should be checked as well as Tom said. They often have a spot* where the resistive film has worn through. Re-routing the wiper arm could solve that for a while. (*where the wiper resides during cruise)

 

 

[Richard309Sri XU5JA 205GTi 7]

I noticed my old AFM has one position about half open where it sticks. 

 

I thought it was because it was dirty so I cleaned it out but still does it 

apparently as we discussed it is the bearings that go