dodge charger falls and stalls slightly when cold. Won't rund when hot.

[Wietse]

When it runs like crap, monitor the AFR ratio on the display and see what it tells you.
Sensor could be at fault, the EFI is programmed to enrich the fueling when the coolant is below 160F (or 165F?), once the temperature goes above it will follow the pre-programmed AFR value.
If the AFR sensor is at fault it will be unable to maintain it.

Since you mentioned you did not change anything else something must have given up, as others mentioned it could be the ignition as well but having a look on the AFR is an easy check.

 

[josephqatarcarguy]

Check these in the below order mate

Any Fault codes
AFR readings/ sensor
IAC steps
Ignition coil / box
Fuel pump / fuel pressure

 

[1970charger440]

When it runs like crap, monitor the AFR ratio on the display and see what it tells you.
Sensor could be at fault, the EFI is programmed to enrich the fueling when the coolant is below 160F (or 165F?), once the temperature goes above it will follow the pre-programmed AFR value.
If the AFR sensor is at fault it will be unable to maintain it.

Since you mentioned you did not change anything else something must have given up, as others mentioned it could be the ignition as well but having a look on the AFR is an easy check.

Thanks for the insight. I have replaced everything on the ignition side, coil, distributor, ignition box, voltage regulator, ballast resistor, but it acts exactly the same. The air fuel ratio reads around 13 when running. If you give it a good rev it will jump real high into the 20's and 30's for a split second. Not sure if that is normal. I've put in a new O2 sensor and also moved the sensor to the collector pipe (stock manifolds) about 6" below the flange. Also no change. It almost runs normal cold. Idles fine but slight hesitation when you rev. Can drive it down the street with minimal backfire. But once it gets warm, it will not idle and cannot handle a load no matter what the RPMs are. Cannot put it into gear without dying.

 

[1970charger440]

Check these in the below order mate

Any Fault codes
AFR readings/ sensor
IAC steps
Ignition coil / box
Fuel pump / fuel pressure

No fault codes.
AFR readings are around 13 while running. When you rev it, you'll see them jump to 25-30 for a split second.
Tried replacing O2 sensor and moved it up on the exhaust pipe about 6" after flange with stock manifold on passenger side.
Sent data logs to Holley. they think there is air getting into the system.
checked for vacuum leaks.
All the ignition parts have been replaced with no improvement. Coil, distributor, ignition box, voltage regulator, ballast resistor, alternator, battery. No change at all.
I have pressure gauges on both sides of the EFI. Pressure is 58 lbs and consistient. If you slam the throttle you can see the pressure fluctuate for a split second (no more than 3 lbs). 2-3 lbs resistance on return side.
Re-grounded pump. Upsized and replaced fuel line from tank to EFI in 3/8.
Still no improvement.

 

[AR67GTX]

I’ve read and heard a number of different things. I’m no expert. Stock sticker indicates 2.5 degrees. But it ran well for years there. No change to motor.

5 degrees is deep in smog motor territory. I would get a dial back light and power timevthe engine to 35 degrees total advance with the vacuum advance plugged. You will need to rev it up high enough to be sure all the mechanical advance comes in. Then let it idle back and see where the base timing ended up. Hopefully it’s at least in the 10 to 12 degree range. If not you may need to work on limiting the amount of centrifugal advance so you can run more base timing.

But. . . This is probably not the solution to what is currently ailing the motor. It’s probably just accentuating the issue.

 

[Sixpactogo]

It sounds ignition related to me. Not fuel. With that nice shiny white paint on the firewall, I'm wondering what kind of reading an ohm meter would come up with on that orange box. A bad case ground on that orange box will do what your experiencing even with a older problem free orange box. The newer ones appear to be junk according to what I've heard. I have not had one fail since I learned many years ago about the grounding issue. If you have more than .5 (1/2) ohms between battery neg and the orange box case, even a good ECU will get hot and open the transistor causing a no spark condition. You have jumped through a lot of hoops trying to sort out the problem but from what I have read in this thread, a proper ground has not been verified. It could also be the plate coil in the distributor but usually when they fail, they don't heal themselves up like the ECU does when cooled down.

 

[kiwigtx]

The tick could be an exhaust leak (which could also get worse with temperature) and if it's on the same side of the O2 sensor it would get an incorrect reading so the EFI might be adding in the wrong amount of fuel.

This ^^^^

Also, did you send a copy of the Sniper SD card program to Holley for them to check? @1970charger440

I have my initial set at 15 degrees on the Sniper I system I have. I have also made a copy of the original program so that if I play around and it all goes wrong, I can reload the original program.

Settings are not available to adjust on a Sniper until it reaches 160 degrees. Don't go adjusting anything until then.

****Also check that you have all the vacuum lines installed, and they are going to the correct ports - do not guess where to put them. There is a picture in the Sniper manual showing where they go

 

[1970charger440]

5 degrees is deep in smog motor territory. I would get a dial back light and power timevthe engine to 35 degrees total advance with the vacuum advance plugged. You will need to rev it up high enough to be sure all the mechanical advance comes in. Then let it idle back and see where the base timing ended up. Hopefully it’s at least in the 10 to 12 degree range. If not you may need to work on limiting the amount of centrifugal advance so you can run more base timing.

But. . . This is probably not the solution to what is currently ailing the motor. It’s probably just accentuating the issue.

I had the dist dialed in before I changed it (35 degrees total). Problem now is that I can only set initial timing because it doesn't run when warm. I'll play around with this though and see if I can get a change. I appreciate the response and assistance.

 

[1970charger440]

This ^^^^

Also, did you send a copy of the Sniper SD card program to Holley for them to check? @1970charger440

I have my initial set at 15 degrees on the Sniper I system I have. I have also made a copy of the original program so that if I play around and it all goes wrong, I can reload the original program.

Settings are not available to adjust on a Sniper until it reaches 160 degrees. Don't go adjusting anything until then.

****Also check that you have all the vacuum lines installed, and they are going to the correct ports - do not guess where to put them. There is a picture in the Sniper manual showing where they go

I really appreciate the help and perspective.

I downloaded the file from SD card and emailed to Holley. They said it could be a bunch of air getting in or a valve train issue. I've replaced lines and don't see air being a possibility at this point. Made sure things were tight.

I'll try more timing and see it that helps, but it ran so well before (for 2 years).

Vacuum lines are installed at correct ports. Unused are cappped. I recently checked all the lines and made sure they held a vacuum.

 

[1970charger440]

It sounds ignition related to me. Not fuel. With that nice shiny white paint on the firewall, I'm wondering what kind of reading an ohm meter would come up with on that orange box. A bad case ground on that orange box will do what your experiencing even with a older problem free orange box. The newer ones appear to be junk according to what I've heard. I have not had one fail since I learned many years ago about the grounding issue. If you have more than .5 (1/2) ohms between battery neg and the orange box case, even a good ECU will get hot and open the transistor causing a no spark condition. You have jumped through a lot of hoops trying to sort out the problem but from what I have read in this thread, a proper ground has not been verified. It could also be the plate coil in the distributor but usually when they fail, they don't heal themselves up like the ECU does when cooled down.

Great observation. I have not put an ohm meter on it, but that is worth trying. Yes, that is some rather new paint and I became concerned about that too. I added a ground wire to ICM and carried it to a wiper motor stud and then to the intake manifold. Used additional star washers to get some bit. I'll sniff around that a bit more. Thank you for the advice.

 

[68Moparmaniac]

Thanks for the insight. I have replaced everything on the ignition side, coil, distributor, ignition box, voltage regulator, ballast resistor, but it acts exactly the same. The air fuel ratio reads around 13 when running. If you give it a good rev it will jump real high into the 20's and 30's for a split second. Not sure if that is normal. I've put in a new O2 sensor and also moved the sensor to the collector pipe (stock manifolds) about 6" below the flange. Also no change. It almost runs normal cold. Idles fine but slight hesitation when you rev. Can drive it down the street with minimal backfire. But once it gets warm, it will not idle and cannot handle a load no matter what the RPMs are. Cannot put it into gear without dying.

Wow your A/F goes to 20:1 30:1? Dude that's way, way lean. When you give it throttle it goes from a happy 13:1 to over 20:1 for a split second correct? But the A/F corrects it's self? Haven't had the opportunity to play with the Sniper system but I'm thinking check the fuel map (if your system has data logging) because that is suspiciously a dead lean condition on tip in which will cause your "stumble". If the engine ran well for 2 yrs. and 3000 miles and then it just went south for no reason, it could be a component in your system went to ****. Main thing if you have the proper fuel pressure and the injectors are firing then it is possible your issue could be combination of all the above electrical/ignition suggestions..ie. grounds/connections etc. Good luck, I know it can be frustrating dragging these classics into the 21st century, don't throw in the towel just yet because it's possibly something simple. On another note, IMO the initial timing is on the low side for a 440, I run initial @12 w/36 all in, but mine is controlled by the computer. Maybe bump your timing up around 10 and see if that helps.

 

[Wietse]

If you give it a good rev it will jump real high into the 20's and 30's for a split second.

You can reduce that by adjusting the acceleration enrichment on the handheld.
Home screen=>Tuning=>Basic=>Basic Fuel =>Accel Enrich
Check and write down the current value lb/hr fuel (example: 50lb/hr, you can add 10% (55lb/hr) and see how it responds.
Don't throw crazy numbers in there, just go a little at the time.
There is alway a very short lag where the AFR gets behind but should not jump that lean, mine goes 15-16-ish very shortly and drops to a richer value depending on the throttle opening. (manifold vacuum)
Note that the self-learning capability also adjusts this value as it get more data for reference.

 

[1970charger440]

Thanks everyone for your suggestions and help. I finally fixed it and will leave it here in case helpful to someone else.

I’ve been chasing this issue for a year. I’m not sure what the original problem was. Maybe distributor or coil. But ultimately I think I fixed that early in my troubles. While doing that I changed the ballast resistor. And then the problem changed and I could never get it right. Finally was down to the EFI and invested the $1000+ to change it. To my horror, the problem persisted with the new EFI. Not being able to idle then led me to spark, and I put a spark tester on it. Very weak spark on run position. Massive clue.

I started delving into coil specs and then stumbled onto the ballast resister I changed. The ballast resistor part number was not listed for my car. As I looked further it had a much higher resistance. I bought the right resistor and voila! It runs great.

Now it has a pile of new parts.

 

[oldkimmer]

Glad u got it fixed. It was something simple all along. Kim