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Ask Doug Barnowski Your Own Question
Doug Barnowski
Doug Barnowski,
Category: Medium and Heavy Trucks
Satisfied Customers: 6
Experience:  HD Truck Mechanic at VIP Truck Center, LLC
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I have a 1990 topkick truck with a 366 and will not rev up.

Customer Question

i have a 1990 topkick truck with a 366 and will not rev up. it will idle fine. ive replaced the coolant temp sensor,distributor and cap. what else to check? it doesnt have any codes.
Submitted: 2 months ago.
Category: Medium and Heavy Trucks
Expert:  Doug Barnowski replied 2 months ago.

Hi, i'm Doug and will be here to help you today.

If I remember correctly that year Top Kick has a mechanical linkage for the gas pedal. Please find the gas pedal end at engine and have somebode step on gas pedal and watch the engine end and see if the engine end is moving. I have seen the cables brake inside of housing on this model truck.

I hope this helps. Reconnect with me if needed and please rate my work on your question.

Thanks, Doug.

Customer: replied 2 months ago.
The cable isn't broke. When you start to rev it up it just dies out.
Expert:  Doug Barnowski replied 2 months ago.

Hi Greg,

Is there any codes or have they been cleared and is the check engine light on?

I have a list of things that would cause your problem. Please check them out.

Low engine compression

Ignition coil leak or hooked up backwards low,

Fuel pump pressure, should be 9-13 PSI

Old fuel

Vacuum leak, fuel mix will be too lean

Throttle position sensor, out of range or miss adjusted

Spark plugs, incorrect,worn, faulty

Clogged exhaust system, debris inside of pipes or clogged converter

O2 sensors, will result in a lean mixture

Fuel return line, must be not restricted.

Please check these items out and let me know how it goes.

Thanks, Doug

Customer: replied 2 months ago.
I've checked all of the stuff you say check. I put a spark tester on the coil wire on the distributor cap and when I start to rev it up the tester light flickers and if I hold the throttle above idle the light goes out.
Expert:  Doug Barnowski replied 2 months ago.

Sounds like something in the distributor or a bad ignition coil. Also, what about correct voltage going to distributor?

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