Intermittent cold crank, no start 2001 Neon

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Been battling this issue for a 2 years. 2001 Dodge Neon R/T

When warm it starts everytime, even warmer weather infact, cold start it may take 2 tries or even several to get started.

Shot of ether in the intake then engine would start and stay running just fine. Fuel pump had been noisier the past couple years so I put a new denso unit in, quite an easy job in these cars. Even more so with only 2gal or gas in it

This didnt resolve the issue, next was checking the crank sensor and the wiring. Good power and ground at the connector, turning the engine by hand I could see the 5 volt return signal turning on and off. Granted this doesnt mean its good but I carried on to the next thing as I dont have the equipment to look at waveforms

Moved to cam sensor and found the inside of the connector to be quite soaked in oil, not sure how, it does face straight up. Cleaned up the connector and put a new Mopar cam sensor in.

Still having the same issue,

Next I may just go on to a ground connection cleaning. Its frustrating since its so intermittent, and may never happen during the warmer times of the year. This is my winter beater (which its great at being at) so I wanna find the issue, Ive gotten more than my moneys worth out of this car but cant part with it for some reason, been too good to me maybe in the 10 years Ive had it.

Its been near 50F outside the past couple days so my days of being able to crank/no-start and finding the culprit may be coming to an end this year. As it keeps starting fine.

This made me think coolant temp sensor or IAT sensor. I verified the coolant temp reading was accurate to ambient. Intake air temp wouldnt give me a number, I unplugged it and the car threw a code for it and battery light came on (only charging system at 13.5 volts) so it appears IAT sensor is at least doing something. Not sure if I should pursue that further. My sister has an 05 neon, so most things I can easily steal for an afternoon to verify any guesses I may have.

Grounds, or PCM is all I can think of now.
Last week, First try it didnt start, so I put a jumper cable from the neg battery terminal to a stud from the shock tower and it fired up fine, hard to say if that worked or was just a coincidence but Ill try it again or even during cranking with a helper. If I get the chance that is.

Anyway thats where Im at, just thought Id share this with you, and will update on anything new. I dont like firing new parts all over a problem, I really want to find the culprit.
 
Even though you replaced fuel pump, I still suspect low fuel pressure. I would check it with a gauge to see what pressure is at during prime and running. May want to check power to the pump. The shot of either gives it away.
 
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I say the hot or cold sensor in the starter took a [censored]. Get another starter for it. I had that problem on a older Daytona once -- put in a new starter and it fixed it. The mechanic told me the cold sensor went out/died.
 
There is no "cold sensor" in a starter.

The IAT is something that needs to be investigated more, it is important for cold starting.

Low compression makes an engine hard to start cold, though you would also have high oil consumption.
 
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Originally Posted By: BAJA_05
Maybe my mechanic said hot/cold solenoid? My problem was the starter and fixed when replacing with another starter.

Oh, you were being serious with your first post?
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I think your mechanic was messing with you. There is no such thing as a hot/cold sensor or solenoid. And the OP says his car cranks over fine when it's cold, the engine just doesn't start. So his starter is working perfectly fine.
 
Idle air controller sticking, not allowing sufficient enrichment? Assuming you've checked the temp sensors as others have recommended.

Basically I'd say anything that can skew the mixture too lean for a cold start: MAP sensor, Throttle Position Sensor, IAC, coolant temp sensor, intake air temp sensor, low fuel pressure).

Speaking of low fuel pressure: does cycling the key to "ON" without cranking, and back to off, then "ON" without cranking 2-3 times before cranking it cause a start? That will run the fuel pump for 3-4 seconds every time you turn the key to "ON" and fully pressurize the fuel rail before you crank. If that makes it start reliably, then it may be a leaking injector O-ring that lets the fuel pressure bleed to zero overnight, and then not come up to pressure quickly enough for a normal start first thing on a cold morning.
 
Is there a check valve on the fuel lines that's letting fuel leak back to the tank? Next time throw a fuel gauge on the car before you start it when cold. OR put the car in the run position for a few seconds then start it, if it turns on it may be check valve issue.
 
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I don't like throwing parts at problems, but if the fuel filter has not been changed in a long time I would change it.

From past experience, problems with electrical components/sensors usually malfunction when they are hot. Your problem is when it's cold, so it sounds like to me the fuel mixture is not rich enough/too lean to fire. Hard cold starts is a symptom of a faulty air charge temperature sensor.
 
Battery is good, couple months old. Same issue with the old battery

I'll try to get a means of checking the fuel pressure

Map sensor seems to be working, engine almost stalled when I unplugged it, it recovered and watching the o2 sensors it started running rich, both up and downstream went to 1 volt.

Throttle position sensor at idle says 12% and it does respond when moving the pedal.

IAC I haven't looked at, car does idle fine around 1200 at first then 800ish when warm, unless it does something while starting I'm unaware of

IAT, I may try a different one.

I have a gauge for compression testing so I'll see what the numbers are, although it doesn't consume any noticeable amount of oil over a 10k oci

Fuel filter is part of the fuel pump assembly, so it's new

Cycling the key before starting I've done in the past and it was no help.
 
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Originally Posted By: heyleescomet

Last week, First try it didnt start, so I put a jumper cable from the neg battery terminal to a stud from the shock tower and it fired up fine, hard to say if that worked or was just a coincidence but Ill try it again or even during cranking with a helper. If I get the chance that is.


This is telling. Do you have a power probe? Grounds and IAT is where I would be looking first.
 
I feel the same Trav.

Compression test results, cold engine no time to warm it up, same number of turns for each, all sparks plugs out, throttle wide open. Only did it dry, no wet tests.

1-211psi
2-209psi
3-210psi
4-203psi

Seems good to me for a neon engine with 200k. Keep in mind this is the r/t engine with the magnum head and I think it has higher compression, not sure on the exact number though.
 
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