Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

[VIPERRACING]

Guys, I have a ultimate 3 bar chip tune & the truck stalls after about 20 minutes of driving or after it heats up & will not start unless idle is turned up or if I open & controll the start up by my foot or unless it sits long enough to cool down. But here's the kicker, When I swap out the map sensor with a 1 bar it will start up & idle totally fine. So I ordered a new 3 bar map sensor because I figured that was the problem but its doing the same thing after it heats up as before. So to double check I swapped in the 1 bar after the truck wouldnt start and it started right up and once again held idle perfectly & then I swapped it back out to the 3 bar and once again no start unless I open the throttle blades by foot pedal or by turning up the idle with the throttle stop screw. I have already swapped out the iac with a new one thinking that was the problem first before messing around with the map sensors. The truck has a mild build(4-bolt forged short block, l-35's, 412, pte 52, 50lb inj, ultimate 50 chip). Thanks again for any and all help.

 

[VIPERRACING]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

I didnt think that I was going to see anyone with this issue. Im used to having standalone systems on my vehicles and was hoping to not have to add one to this truck since its just a mild build. Well if anyone can think of anything please let me know. Thanks

 

[powercat6]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

The coolant temperature sensor that serves the ECM failed in my Typhoon 3 months ago.

This caused a flooding/no start condition when it was hot like you're experiencing. My Ty never stalled because of the bad sensor though.

Consider checking the sensor and the circuit itself. This is the sensor located in the intake manifold below the throttle body linkages.

 

[VIPERRACING]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

The coolant temperature sensor that serves the ECM failed in my Typhoon 3 months ago.

This caused a flooding/no start condition when it was hot like you're experiencing. My Ty never stalled because of the bad sensor though.

Consider checking the sensor and the circuit itself. This is the sensor located in the intake manifold below the throttle body linkages.

I thought about that first until I swapped out the map sensor with a 1 bar and it started up instantly which made me think that my 3 bar map was bad. So did your truck run perfectly fine until it got up to temp? Mine runs perfectly fine until it gets hot enough(about 20 minutes of driving) or if I turn it off after a quick spin and the under hood temps get everything warm enough to cause it not to start unless I control the idle via opening the throttle body with my foot. Besides that the truck runs fine until it comes to a stop or close to a stop in which I have to two step it to keep it from stalling out. It will fire right up after everything cools down. Thanks

 

[powercat6]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

Mine seemed to run and idle fine, but the check engine light was on (Code 15 Coolant Temperature Sensor Circuit) when I had the problem.

I had just driven about 5 miles to a gas station. I shut the engine off aired up my tires and went to restart and it would only crank. Mine would also restart after some cool down time.

I have a stock chip BTW.

 

[VIPERRACING]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

Mine seemed to run and idle fine, but the check engine light was on (Code 15 Coolant Temperature Sensor Circuit) when I had the problem.

I had just driven about 5 miles to a gas station. I shut the engine off aired up my tires and went to restart and it would only crank. Mine would also restart after some cool down time.

I have a stock chip BTW.

Ya I have a ultimate chip which is one of the reasons why Im most likely not getting a check engine light.

 

[Davemc1963]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

I have had a coil start to breakdown when it got hot. (not on the Ty though) Started OK, but when it got hot, it would falter badly under load, it felt a bit like it was running out of fuel and I had to feather the throttle to keep it running. I know you say it starts right up when you cahnge the MAP sensor, but this may give it just enough time to cool down. Just a thought, it could be also your ignition module or wiring to the distributor. Other than that check/remake all the connections to the distributor and the ecu and re-seat the Ultimate and maybe even the piggy-backed original memcal to the carrier.
I have also had a bad (and fouled) plug cause problems too.

 

[skraypngm]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

Similar issue a while back turned out being the ignition module...good luck!

 

[VIPERRACING]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

Skraypngm & Davemc, Thanks for your input but the truck runs perfectly fine besides it wont hold idle after it get warmed. An ignition module would cause the truck not to run which isnt my problem & the map sensor was switched on & off when the truck was acting up & it would start everytime and hold idle with the 1 bar but not with the 3 bar unless left to cool down which would eliminate a bad ignition module. Im going to switch out the coolant sensor sense that was on the top of my list but over looked it after thinking it was a faulty map sensor which to find out wasnt. Thanks again for all your inputs it truly appreciated, tony.

 

[Davemc1963]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

Tony, regarding the ignition module, it should have heat sink grease under it, it it doesn't, or it has dried out, it will break down when it gets hot as it wont be able to transfer heat properly to the distributor body which it uses as a heat sink. This will cause the module to overheat and probably eventually fail. This is the same for most HEI's as far as I know. When the affected components cool down again, it will function again, (for a while!). There are various types of heat sink grease and I have seen some of the 'white' greases sold by some electronic outlets go hard with age. It also depends who has owned the truck before you. Not all modules immediately fail outright, there is often a root cause for their demise.

 

[VIPERRACING]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

Tony, regarding the ignition module, it should have heat sink grease under it, it it doesn't, or it has dried out, it will break down when it gets hot as it wont be able to transfer heat properly to the distributor body which it uses as a heat sink. This will cause the module to overheat and probably eventually fail. This is the same for most HEI's as far as I know. When the affected components cool down again, it will function again, (for a while!). There are various types of heat sink grease and I have seen some of the 'white' greases sold by some electronic outlets go hard with age. It also depends who has owned the truck before you. Not all modules immediately fail outright, there is often a root cause for their demise.

Thanks for the info. I know what your talking about but the truck fires right up if I open the tb so that tells me that the module isn't the problem because it would cause the truck not to run at all until cooled down if it was bad. I did change out the map, coolant temp sensor yesterday and drove the truck and the same thing happend again after about 20 minutes of driving. But heres the kicker, when I lowered the fuel pressure via afr it starts right up. Not sure if the afr is causing the problem or not. I pulled the line and its dry. Can some one please ohm out their coolant temp wires going to the ecm for me. Im thinking that cold also be a problem after it gets hot. I think mine read somewhere around 4.XXohms when cold. Does anyone have their stock regulator & injectors that they can let me barrow to see if that solves the problem? Thanks

 

[powercat6]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

This might be what you're looking for:

http://www.syty.org/old/d&e-code15.html

 

[VIPERRACING]

Re: Need some help!! Truck wont hold idle when hot with 3 bar map ultimate chip

This might be what you're looking for:

http://www.syty.org/old/d&e-code15.html

powercat, Thanks so much I will give it a shot. Im so used to having standalone systems on most of my cars but I decided to keep this truck as a mild build & try to stay with the stock ecm. Ill keep you guys updated. Im also thinking that my regulator may be bad even though its not spitting fuel out of it but once I lowered the fuel pressure it ran and held idle. Ill check to make sure that the ecm is reading properly and then make my way to the regulator. Thanks again, Tony.