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Old 02-16-2003, 11:25 AM
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zorin zorin is offline
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Join Date: Feb 2003
Location: Ottawa, Canada
Posts: 126
Cool Poor throttle response, hard start

Hi all,

I am fairly new to this awsome forum. I have been reading a lot of posting and have learned a lot. However I have not yet been able to solve my problem on my 88 E260:

The problem (symptoms) :

- Intermittent poor throttle response
at which time I have to pump the gas pedal few time to get it going

- Hard start
as if not enough gas making it to the cylinders. Sometimes after a few seconds of engine running it stalls even though I press on the gas pedal .

What I have done so far:

- Used few bottles of fuel injection cleaner in the tank
- Change the fuel filter twice in the last 3 months
- Changed the spark plugs
- Put new spark plug wires
- Checked the distributor and rotor cap - cleaned them - no cracks so I put them back
- Checked for the resistance of ignition coils - both are OK
- took out the starting valve, cleaned it, made sure it opens and spits fuel (couple of CC's). Also made sure that the relay does send the proper voltage to the starting valve when cold
- Took out the injection valves, cleaned them. While one of the injection valves was still out I screwed back in the fuel line to it and had someone crank the engine. Did not see any fuel come out. Maybe it should not anyways. (No vacuum!)
- Cleaned the strainer at input fuel line to the distributor - was dirty - cleaned it
- checked the fues on OVP - was OK
- fuel filter does start when ignition is turned on
- checked the fuel volume deliverd, by bridging jack 7 and 8 - was ok
- took out the idle controller, and cleaned it. made sure the pipes to it are tight
- checked the voltage on Throttle Valve Switch - OK
- checked the voltages on pins of Air Volume Meter - OK
- Checked the resistance of coolant temp sensor at different temperatures. It matched the specs
- cleaned and lubricated throttle cables
- Air filter is new

The car idles fine and when it does respond to throttle the acceleration is very good.

I do not hear any hissing sound and do not know how to check for vacuum leaks.I did some spray testing but that did not show any problem. I also noticed that unplugging the think hose from air intake black return hose does not make any difference in engine idle speed. I also unplugged the vacuum hose from EZL fot few seconds but did not make any change in idle speed either

On the highway at steady high speed the car runs flawlessly.

Can anybody please let me know what else I should check (and maybe how)

Thanks .

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