Symptoms:

I have this 1992 Dodge starting problem on my Daytona car which I replaced the engine 2 weeks ago. I replaced the engine because it was using lots of oil. Other than that, it was running fine. Once the engine was replaced, it would run only when cold but quit when warmed up. Before quitting, I would have to press the gas pedal to keep it running like it was losing fuel. What is causing this?

Vehicle description:

1992 Dodge Daytona with 2.5L rebuilt engine with TBI fuel injection system. A complete tune up was done including new distributor cap and rotor, plugs and wires including all necessary filters.

Diagnostics for 1992 Dodge starting problem:

There are 2 ways to test this: the easy way and the hard way. Let me discuss the hard way first because once it is done, everything will be gravy.

Hard way of testing 1992 Dodge starting problem:

This assumes you have no scanner and you wanted to test the rebuilt engine manually. This is done usually by using the troubleshooting basics: any automotive engine needed 3 items in order to run: good supply of air, spark and fuel. Here are questions you need to satisfy:

Engine Air Supply:

The quickest way to test engine air integrity is to undo the air filter cover and cover the throttle body opening during idle. The engine should quit otherwise, it is getting air from other sources called vacuum leak.

what is the engine vacuum reading during cranking? Should be around 3-6 inches. Any reading lower than this is again a mechanical problem.

When engine is cold and running, what is the engine vacuum reading at idle? Reading should be around 17-20 inches of Hg(mercury) using a cheap vacuum gage. Reading like 15 inches Hg or less again points to a mechanical problem like a jumped timing belt.

With engine running and before it quit, have you tried opening the exhaust for possible muffler restrictions? An engine that cannot breathe will die when warmed up.

Engine Integrity Test:

what is the engine compression? Anything cylinder reading lower than 100 psi will make the engine a suspect.

Tip:

A good way to check the engine quality is using a cylinder leak down test. All cylinders should have 10%-30% leakage, higher than this means a defective engine.

Ignition Quality Test:

What is the color of the spark during no start? It should be a strong blue and continuous. An orange color with interruption is an indication of a weak ignition.

What is the ignition timing? Should be between 20-25 BTDC (idle) and around 35-50 at high idle. Before the engine quit, monitor the timing so you can check if it is deviating which will indicate an ignition failure.

During replacement of the engine, were all the ground connections accounted for? A quick way to test this is to access the engine computer (ecm) and test all the ground wires reading. None of the wires should read higher than 0.250v and with key on engine off, the ecm reference voltage should read 5 volts.

Easy way of testing 1992 Dodge starting problem:

The best and quick way to test this 1992 Dodge starting problem is to get hold of a compatible OBD1 scanner which can display engine live data when the engine is started. Using the monitor display, it must show ignition and fuel characteristics like ignition timing, fuel trim and sensor readings. This way, you can see exactly what the engine is doing before it quits. A good scanner for this vehicle can be bought between $200-$300 but will save you a lot of time. Otherwise, a small garage can do it for you for about $100-$150 but make sure you covered all the basic testing before you bring it to them.

Final fix for 1992 Dodge starting problem:

Here is the email sent to me by ATS member after he got it fixed:

Just wanted to let you know that I have finally solved the problem. It was the distributor. The plate in the base of the distributor that interrupts the magnetic field of the hall effect sensor was loose and had movement of about a 16th of an inch. I knew that it should not be there, and could see no way to adequately repair it, so I went out and bought a new (rebuilt) one. The car started right away and continued to idle with no problems. I put the engine through the full rpm range several times and restarted it several times with no issues.

Thank you very much for your help in eliminating what it wasn’t. I no doubt saved quite a bit of money by not having to replace parts that I didn’t need.

Thanks!