reluctant to rev up/accelerate

[aqstar]

I have just purchased a 300CE-24 auto of 1990.

There are no problems with it except:

When I instantaneously floor the gas (on D), the car will momentarily hesitate (about 1 second) to accelerate, then out of sudden the power just rushes in and the car will just speed up without any hesitation. This is only obvious when the engine is hot. Even when the tranny is not engaged i.e. on N or P, the engine will reluctantly rev up when a sudden floor on the gas. However, if step it progressively, it will pose no problem at all. Just to add up, occasionally find it difficult to crank (fire up) the engine on the first attempt when the engine is hot. Could those two problems related?

Any help to solve this problem is greatly appreciated.

cheers

 

[wscheffer]

Welcome to the forum!

I don't be leave that both problems are related. The first one on the hesitation might be a simple adjustment to your throttle linkage and the other is your starter. :mrgreen:

 

[aqstar]

thanks William for your feedback. however, I doubt so that the throttle linkage is the culprite coz the 'flat-spot' only happened when the engine is really hot like during stop and go traffic....

cheers

 

[wscheffer]

Maf

Possible dirty MAF causing slight hesitation, their is a nice thread on how to clean your MAF in the forum.

This could also be the open throttle switch, which would require the throttle body to be switched out since the switch is not sold separately and can be quite costly. But before doing this I would have diagnostics ran to try to isolate the problem.

 

[aqstar]

hi everyone,
just wanna update what i've done ever since:
1) change the ignition coil - result: the problems still there.
2) change the plug wires - result: negative.
3) change the charcoal filter - result: negative.
4) change the fuel filter - result: negative.
5) change the OVP - result: negative.
6) change the micro switch at the throttle linkage - result: negative
7) change the fuel accumulator - result: the flat spot still there but engine fire up with 1 or 2 yank. previously, 4-5 times when its hot. however, still earlier days coz just change it (accumulator) today, need to try it for a few days to justify it.

i'm at lost now! anybody out there can give me some inputs on this, i'm greatly appreciated.

cheers.

 

[Ian B Walker]

Try the crankshaft sensor and check the wiring on the electro magnetic advance and retard gubbins at the front of the inlet cam. They can short out and retard the ignition.

 

[kid-jensen]

agstar,

I've got a Crankshaft sensor you can have cheap If you want it......

 

[Renoir]

Catalyzer?

A friend of mine on this engine had it ripped out (i'ts still ok in Latvia) and the car went like crazy since then. Before, he couldnt even drive faster than 80kmh.

 

[IAN MAC]

I had exactly the same symptoms on an old Ford i had, turned out to be a bad connection to the teperature sensor. Both problems were solved at the same time and it never missed a beat after that. Give it a go

 

[aqstar]

thanks for the replies guys.

btw while the engine is running, unpluged the fuel governor's socket, and noticed no diff on engine speed...flat spot still there too. is this normal? could the switch be the culprit?

cheers

 

[Glenn Smith]

This model has a VAF (volume air flow sensor) this is the old mechanical type with potentiometer, generaly very reliable and it sounds to me like this is the problem, also check very carefully for air leaks between the sensor and engine.

 

[aqstar]

is VAF same as MAF and wheres it located at my engine?

cheers

 

[aqstar]

Had replaced the pressure regulator. As the result, throttle is more responsive and no more flat spots. Hope this should do it.