idles and runs but dies after a couple minutes

All Megasquirt 1 support questions. See also the Documentation

Moderators: jsmcortina, muythaibxr

Post Reply
1seymour
MS/Extra Newbie
Posts: 31
Joined: Fri Nov 25, 2005 3:38 pm
Location: Rockford, IL
Contact:

idles and runs but dies after a couple minutes

Post by 1seymour »

fires right up. has pep and runs ok. after warmed up, if i try to keep the rpms at around 1200-1300, it will hold for a few seconds but then start slowly getting worse and worse. starts with a little miss here and there and progressively gets worse until it misses bad and giving it any throttle results in stumbling and an occasional backfire. after the car dies or i turn it off, if i wait a few seconds and start it back up, it will fire right up and do the same thing again if i rev it. it goes from firing up and idling to bogging out quicker after it's done it once.

i've checked the timing during this behavior with a timing light and it looks good. i've checked that the injectors are getting power with a noid light and they are.

any ideas of what else i should check? anyone know what this might be?

ms-I v3, mt 2.25, code 029q2
1983 datsun 280zx turbo
ms v3 running msns-e 029q2
input: optical
output: vb921
injectors: pwm
chrispel
Helpful MS/Extra'er
Posts: 83
Joined: Sat Mar 19, 2005 9:37 am
Location: Buffalo

Post by chrispel »

Was it working fine before or is this a new setup?

If it's new what do you mean by after it's warmed up? Like what temp is the coolant at?
1seymour
MS/Extra Newbie
Posts: 31
Joined: Fri Nov 25, 2005 3:38 pm
Location: Rockford, IL
Contact:

Post by 1seymour »

new install.

im using the cylinder head temp as the coolant temp input. the car runs for 2-5 minutes and the head temp reads about 175.

the car will idle but if i rev, it bogs down and won't idle until i've restarted it.
1983 datsun 280zx turbo
ms v3 running msns-e 029q2
input: optical
output: vb921
injectors: pwm
1seymour
MS/Extra Newbie
Posts: 31
Joined: Fri Nov 25, 2005 3:38 pm
Location: Rockford, IL
Contact:

Post by 1seymour »

1983 datsun 280zx turbo
ms v3 running msns-e 029q2
input: optical
output: vb921
injectors: pwm
1seymour
MS/Extra Newbie
Posts: 31
Joined: Fri Nov 25, 2005 3:38 pm
Location: Rockford, IL
Contact:

Post by 1seymour »

my msq file.
1983 datsun 280zx turbo
ms v3 running msns-e 029q2
input: optical
output: vb921
injectors: pwm
1seymour
MS/Extra Newbie
Posts: 31
Joined: Fri Nov 25, 2005 3:38 pm
Location: Rockford, IL
Contact:

Post by 1seymour »

warmup data log.
1983 datsun 280zx turbo
ms v3 running msns-e 029q2
input: optical
output: vb921
injectors: pwm
1seymour
MS/Extra Newbie
Posts: 31
Joined: Fri Nov 25, 2005 3:38 pm
Location: Rockford, IL
Contact:

Post by 1seymour »

left the car sitting for 3-5 minutes while looking at warmup log and then fired it up again. it died a couple times in this one.
1983 datsun 280zx turbo
ms v3 running msns-e 029q2
input: optical
output: vb921
injectors: pwm
1seymour
MS/Extra Newbie
Posts: 31
Joined: Fri Nov 25, 2005 3:38 pm
Location: Rockford, IL
Contact:

fixed

Post by 1seymour »

i found the spark was cutting out under accel but was ok at idle (but would slowly get worse to where it won't even idle). i double checked the dwell with a dwell meter and ms was accurately controlling it at 4.0ms. i decreased dwell time to 3.5ms and the issue has gone away.
1983 datsun 280zx turbo
ms v3 running msns-e 029q2
input: optical
output: vb921
injectors: pwm
1seymour
MS/Extra Newbie
Posts: 31
Joined: Fri Nov 25, 2005 3:38 pm
Location: Rockford, IL
Contact:

oops.. not fixed

Post by 1seymour »

since i had it idling and could rev while sitting still, i thought it was fixed. i took it for a spin and after just a few blocks, it started happening again. i turned down the dwell again, this time to about 2.0 and it cleared up but the car ran poorly. it seems like i can't get my dwell low enough for continued operation and can't get it high enough for optimal operation. something's got to be wrong. any ideas?

cranking dwell: 6.0
running dwell: 3.0
minimum discharge: 1.0
1983 datsun 280zx turbo
ms v3 running msns-e 029q2
input: optical
output: vb921
injectors: pwm
Post Reply