Hesitation or lurching between 2200-2800rpm

[joehahn]

Hi all,

Car running great hence no recent posts (75 2.0L) but every morning I have the same problem UNTIL the car is warmed up. For some reason the engine lurches or lunges between 2200 and 2800 RPM until the engine temp needle moves about a quarter of the way over. If I simply wind it right through this spot and let it drive at around 3,000 then no problems. Doesn't matter what gear I am in but seems to be most persistent in 4th. Again, it completely disappears after warm up. Am I making something out of nothing?

Thanks in advance,

Joe

email = monish@ix.netcom.com

[This message has been edited by joehahn (edited 08-31-1999).]

[Brister]

I wonder if your engine is carburated.. my 73 1.7 is carburated and I don't have that problem but it does occur with my Healey from around 1000 to 2000 rpm until the engine warms slightly. I have always assumed it was a matter of the manual choke not being set correctly and just give it the gas until it smooths out.

[S Schroeder]

I agree with Bill. My carbed 2.0 used to to this until they were finally jetted and synced(sp?)up correctly. I did experience a similar feeling when a ground wire had come loose inside the destributor, on the lower triger points. These points and ground are located under the plate that supports the upper points that we are all used to adjusting.
My $.02 -
Scott S

[joehahn]

Actually it is still fuel injected

[John Rogers]

Our 1974 914 did this recently and after cleaning and resetting the throttle position switch it went away. Ours did it at all temps, but it never gets really warm anyways?

[Dave at Pelican Parts]

If the car doesn't lurch with the throttle position switch unplugged (it should run, but accelerate poorly) then the TPS is at fault. Cleaning the contacts (both the plug and the switch side of the plug, AND also inside the plug!) and adjusting the switch may fix it, or may not.

If that isn't it, you have to start the basic FI diagnostic procedure. That always (always ALWAYS) starts with the ignition. Check your timing and dwell, inspect the points, check the color and condition of the spark, check the color of the plugs.

Next, move on to the most temperature-sensitive part of the FI--the head temp sensor. Make sure its resistance is ~1500-1800 ohms cold, and <100 ohms when the engine is warmed up. Clean the connector.

Check the multiple grounds at the rear of the top case seam. Clean and tight is the rule. Check for vaccuum leaks--unlikely to be the root of the problem, but possible (I think). Make sure the MPS is OK, that it holds a vaccuum and the windings aren't shorted.

Kjell Nelin's D-jet article on the 914 Fan Page http://www.914fan.net has most or all of the tests. A well-written article, well worth a read.

Good luck!

--DD