Hot Starting Issue

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Tammaru

Well-known member
Oct 19, 2007
164
0
New Jersey
Hi,

I have a strange issue that I can't seem to figure out. Every now and then after I've driven for a while, stopped and turned the car off and then tried to start the truck when it is hot, it will run rough idle will go quickly from 750 to 0 and it will stall, if it gun the gas and get going, idle goes up and it acts like normal again. It does this about once a week, most of the time it starts right up like normal. It never does this when the car is cold. Things I can rule out....

Fuel pump is new.
Fuel pressure regulator is new.
Tested the fuel injectors and they are not leaking, also the o-rings on the injectors are new.
Fuel Temp sensor is new.
Coolant Temp sensor is new.
Stepper motor is new.
TPS is new.

I'm thinking maybe I'm getting vapour lock, but why would it just start happening? Are there any other sensors that could be causing this at random times? This never leaves me stranded, but sometimes it's a pain when you start it up and it stalls right out. Any help would be great! Thanks!

T
 
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Mitcheath

New member
Sep 20, 2009
1
0
Tacoma, WA
I'd also be interested in hearing any ideas on this one. The same thing happened to me this summer with my 96 disco. It only happened when the engine was hot and the outside temp was over 90 degrees. We don't get that kind of weather around here for too long, so I just lived with it for a week or so and it hasn't happened since.
 
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Tammaru

Well-known member
Oct 19, 2007
164
0
New Jersey
Mitcheath said:
I'd also be interested in hearing any ideas on this one. The same thing happened to me this summer with my 96 disco. It only happened when the engine was hot and the outside temp was over 90 degrees. We don't get that kind of weather around here for too long, so I just lived with it for a week or so and it hasn't happened since.
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I've been reading a lot of posts about hot starting issues and it seems that sometimes the fuel pump relay itself has an issue and overheats and then malfunctions, so I ordered a new one. I'll let you know if it fixes the issue.
 
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alexvonryzin

Guest
I had the same problem.....
I replaced the tps,idle control valve....mass airflow sensor...full tune up...seafoamed the crap out of it to release carbon buildup...checked for vacuum leaks...fuel pressure regulator....the list goes on and on.

Then searching on the internet i came across this thing called an Ignition Amplifier Module..
which is located on the right side of the radiator....next to the power steering resivor .

apparently when this thing gets to hot...it creates hard hot start problems....i never had a problem with cold starts....but when im in the woods...and i shut the truck of...and go to restart..it does exactly what you described....idle revs to 1500 rpms...slowly drops down to normal idle...sputters a bit when i put in drive....then it seems to be fine...once im going....i dont know if mine is on its way out....but ive learned to put up with it.

Atlantic British has a re locator kit...to get it away from the radiator...but its pretty expensive...

Anyway...my two cents...

Good luck.
 
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alexvonryzin

Guest
The ignition amplifier module is a notorious cause of hot stalling and stuttering. Dean Sonneborn found the heat buildup under the hood when his 1990 RR was not moving (eg stopped at traffic lights) caused his ignition amplifier module to fail intermittently, stalling the engine. The faulty unit was so sensitive to temperature that even a minute or two of cooler air provided by opening the hood got it working again.
 
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Tammaru

Well-known member
Oct 19, 2007
164
0
New Jersey
Fuel pump relay didn't help the issue. The hard stating hasn't been as bad as it has been recently though. Never heard of the ignition amplifier before, it's on the right side by the radiator and power steering pump? There must be some way to relocate it without paying Atlantic British $400.
 
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robertf

Well-known member
Jan 22, 2006
4,799
366
-
alexvonryzin said:
The ignition amplifier module is a notorious cause of hot stalling and stuttering. Dean Sonneborn found the heat buildup under the hood when his 1990 RR was not moving (eg stopped at traffic lights) caused his ignition amplifier module to fail intermittently, stalling the engine. The faulty unit was so sensitive to temperature that even a minute or two of cooler air provided by opening the hood got it working again.
Click to expand...

96+ NAS Discos don't have those
 
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