Roadmaster issue
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 72
Likes: 11
Roadmaster issue kinda long, will try to be brief.
the car:
1995 roadmaster, bought it for my son's first - it's too big/ugly/whatever -
now I drive it as a daily and abuse it sometimes at the dragstrip.
stock motor 178k miles
3.42s, yukon duragrip, 245/60-15s all around
fresh valve springs
home depot intake
speed daddy stainless headers [1 5/8 'clipster']
2.5" exhaust, h pipe
WBO2
EGR/ABS/AC/A.I.R deleted
fresh 4l60e with idk what converter [logger sez flash stall 2400 rpm]
tuned by me
14.66 @ 92.5 mph, 2.045 60'- 1800' DA, 4450# as driven.
the problem:
every once in a while the car will miss fire/sputter.
usually [but not always] on rapid throttle transition.
i have a hard time getting it to occur/repeat.
happens to me maybe once every other week.
getting out of it [throttle] and back in seems to help some.
hold it to the floor and it will continue to miss fire.
10 mins later the car is fine [wtf?]
been chasing this issue since late june.
what I have done so far:
replaced bad MAF
bought a flea bay [not AC Delco] opti - "with proof that it works". Came
with a new vent harness too.
new plugs/wires
warranteed an OReilly opti and bought new pigtail [problems with an ebay
purchase? outrageous
]
verified fuel pressure [got lucky and had the car act up with the gauge
taped to the windshield] at WOT thru 1st gear at ~50 psi and not dropping.
Couldn't see anything in my data logs that was off either.
swapped coils, new icm and cts and all new pigtails/connectors
new tps
new intake gaskets [rear china wall leak]/injector o rings. Vac gauge tells
me 23" at hot idle in park.
more data logging and still not seeing anything odd
used a spacer to get the icm/coil off the head a bit
car did it again on my drive to work today.
the car:
1995 roadmaster, bought it for my son's first - it's too big/ugly/whatever -
now I drive it as a daily and abuse it sometimes at the dragstrip.
stock motor 178k miles
3.42s, yukon duragrip, 245/60-15s all around
fresh valve springs
home depot intake
speed daddy stainless headers [1 5/8 'clipster']
2.5" exhaust, h pipe
WBO2
EGR/ABS/AC/A.I.R deleted
fresh 4l60e with idk what converter [logger sez flash stall 2400 rpm]
tuned by me
14.66 @ 92.5 mph, 2.045 60'- 1800' DA, 4450# as driven.
the problem:
every once in a while the car will miss fire/sputter.
usually [but not always] on rapid throttle transition.
i have a hard time getting it to occur/repeat.
happens to me maybe once every other week.
getting out of it [throttle] and back in seems to help some.
hold it to the floor and it will continue to miss fire.
10 mins later the car is fine [wtf?]
been chasing this issue since late june.
what I have done so far:
replaced bad MAF
bought a flea bay [not AC Delco] opti - "with proof that it works". Came
with a new vent harness too.
new plugs/wires
warranteed an OReilly opti and bought new pigtail [problems with an ebay
purchase? outrageous
]verified fuel pressure [got lucky and had the car act up with the gauge
taped to the windshield] at WOT thru 1st gear at ~50 psi and not dropping.
Couldn't see anything in my data logs that was off either.
swapped coils, new icm and cts and all new pigtails/connectors
new tps
new intake gaskets [rear china wall leak]/injector o rings. Vac gauge tells
me 23" at hot idle in park.
more data logging and still not seeing anything odd
used a spacer to get the icm/coil off the head a bit
car did it again on my drive to work today.
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 72
Likes: 11
sometimes, not always.
I was thinking it was from me repeatedly mashing it from a 40 mph roll [with the engine heat soaked on a 90+ degree day] attempting to get it to act up with the logger recording.
bits of kr that way. had it sputter a bit on an onramp [same day/log WOT to the top of 2nd gear] and no kr shown.
I was thinking it was from me repeatedly mashing it from a 40 mph roll [with the engine heat soaked on a 90+ degree day] attempting to get it to act up with the logger recording.
bits of kr that way. had it sputter a bit on an onramp [same day/log WOT to the top of 2nd gear] and no kr shown.
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 72
Likes: 11
nobody?
why am I not surprised so many of these cars end up sold/scrapped/motor swapped...
hopefully it breaks soon and I can find the flipping problem...
the 'get around to it' list includes checking the injectors, and replacing the NB O2's.
waiting on a new laptop battery and will collect some more logs first.
why am I not surprised so many of these cars end up sold/scrapped/motor swapped...
hopefully it breaks soon and I can find the flipping problem...
the 'get around to it' list includes checking the injectors, and replacing the NB O2's.
waiting on a new laptop battery and will collect some more logs first.
TECH Veteran
Joined: Apr 2008
Posts: 4,985
Likes: 112
you have 50 psi of FP at WOT...a bit high.
Not really your miss issue but high.
what are your STFT showing?
The off brand Opti is always suspect
20+ year old cars with some from multiple owners and repairs be it qualified or not...all make finding "intermittent" issues a problem
Not really your miss issue but high.
what are your STFT showing?
The off brand Opti is always suspect
20+ year old cars with some from multiple owners and repairs be it qualified or not...all make finding "intermittent" issues a problem
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 72
Likes: 11
50 psi on a loaner parts store gauge - take that psi# with a grain of salt, some lime, and a shot of tequila.
I still suspect opti and icm...
IIRC on the pre OBD2 stuff it's integrator rather than STFT (or maybe it's an EEHACK thing), waiting on a battery for now.
Need some fresh logs, it's difficult for me to look thru the old logs and try to remember where it was acting up and I didn't take any notes. Haven't logged the car in a couple of months...
Looking at the one log I know for certain the car was acting strange on, the INTs were all between 120 and 135, BLMs all between 120 and 129 (depending on the cell etc...).
I still suspect opti and icm...
IIRC on the pre OBD2 stuff it's integrator rather than STFT (or maybe it's an EEHACK thing), waiting on a battery for now.
Need some fresh logs, it's difficult for me to look thru the old logs and try to remember where it was acting up and I didn't take any notes. Haven't logged the car in a couple of months...
Looking at the one log I know for certain the car was acting strange on, the INTs were all between 120 and 135, BLMs all between 120 and 129 (depending on the cell etc...).
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Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 72
Likes: 11
Been stupid busy at work so the car has been sitting for the last few weeks. Going home friday evening I noticed the car wanted to idle around 1k rpm (hasn't done it since). Drove it to the shop yesterday (flush coolant, replace O2s and knock sensors) and managed to capture a brief hiccup around record #8396. Also noticed that I could get the car to stumble a bit just stabbing the gas in neutral - at tip in (no logs of this yet).
I should be able to gather some more logs this week...
I should be able to gather some more logs this week...
When it acts up is the weather overly hot? Had issues with my icm getting heatsoaked. Put some washers on behind the bracket to space it off the head so it can breath and solved my problem.
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 72
Likes: 11
Small update:
I checked the oil last week and see that there is some coolant in it. Haven't pulled it apart yet to see what the problem is - assuming I have a cracked head. Never had a head gasket fail before without there being another problem that caused the failure. Thinking all this may have a lot to do with my intermittent miss.
Picked up a used 40k mile motor from a rear-ended '95 Impala SS (been wanting a spare anyways). Replaced all but the head gaskets, refreshed the Delco opti with the MSD C&R kit, new valve seals & springs, plus a few other goodies.
Hoping to have the engine swapped out and running by this weekend...
I checked the oil last week and see that there is some coolant in it. Haven't pulled it apart yet to see what the problem is - assuming I have a cracked head. Never had a head gasket fail before without there being another problem that caused the failure. Thinking all this may have a lot to do with my intermittent miss.
Picked up a used 40k mile motor from a rear-ended '95 Impala SS (been wanting a spare anyways). Replaced all but the head gaskets, refreshed the Delco opti with the MSD C&R kit, new valve seals & springs, plus a few other goodies.
Hoping to have the engine swapped out and running by this weekend...
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 72
Likes: 11
Small update:
had to replace the DS yoke, twisted the old one. I hopped the tires a few times at the track b4 adding a rear sway & new shocks...
Also installed a 10" stall (2900+rpm) and had to tweak the idle timing correction tables to get rid of an idle surge.
Noticed my headers clear the frame somewhat better with fresh motor mounts
Didn't dig too far into the old engine yet but there was coolant getting in to #8 cyl. (wet plug)
Still have a sputter at idle in closed loop only. Seems to want some heat in the motor before it will manifest.
wideband (installed on driver's side) will show a lean dip to 16.xx:1 when the engine is sputtering.
cleaned IAC/throttle body
tps looked good
icm/coil test good
checked 1 3 5 7 wires with a timing light, all looked fine. no intermittent pulse on any while it sputters.
was able to shut down injectors 1 at a time to see if/how it affected the sputter behavior - I couldn't nail it down to any 1 cylinder...
IAC counts are hovering around 16 (throttle blades are closed), bank 1 blms were 135 in cell 16, makes me think vacuum leak
did notice some slow vac leakage on the evap solenoid to canister line (w/solenoid off) so I capped the fitting and drove it a bit, idle sputter remains.
if I lightly touch the pedal when it is sputtering, the car will come out of it.
it will sometimes continue to sputter on initial acceleration.
weather is not too good for any WOT testing (Iowa).
had to replace the DS yoke, twisted the old one. I hopped the tires a few times at the track b4 adding a rear sway & new shocks...
Also installed a 10" stall (2900+rpm) and had to tweak the idle timing correction tables to get rid of an idle surge.
Noticed my headers clear the frame somewhat better with fresh motor mounts
Didn't dig too far into the old engine yet but there was coolant getting in to #8 cyl. (wet plug)
Still have a sputter at idle in closed loop only. Seems to want some heat in the motor before it will manifest.
wideband (installed on driver's side) will show a lean dip to 16.xx:1 when the engine is sputtering.
cleaned IAC/throttle body
tps looked good
icm/coil test good
checked 1 3 5 7 wires with a timing light, all looked fine. no intermittent pulse on any while it sputters.
was able to shut down injectors 1 at a time to see if/how it affected the sputter behavior - I couldn't nail it down to any 1 cylinder...
IAC counts are hovering around 16 (throttle blades are closed), bank 1 blms were 135 in cell 16, makes me think vacuum leak
did notice some slow vac leakage on the evap solenoid to canister line (w/solenoid off) so I capped the fitting and drove it a bit, idle sputter remains.
if I lightly touch the pedal when it is sputtering, the car will come out of it.
it will sometimes continue to sputter on initial acceleration.
weather is not too good for any WOT testing (Iowa).
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 72
Likes: 11
Well, it's official, I am an idiot.
Used a stethoscope to listen to the injectors, of course they all were switching fine.
So that brings me back to a spark issue. Before the engine swap the miss would not show on my wideband - but it did afterwards...hmm
Got the car good and warm then crawled underneath last night and viola, the #5 plug boot was arcing to the header tube (couldn't see it from above).
Pulled the header, dimpled the tube, replaced the boot (plug was ok), doubled up on header gaskets, and no more miss fire.
Used a stethoscope to listen to the injectors, of course they all were switching fine.
So that brings me back to a spark issue. Before the engine swap the miss would not show on my wideband - but it did afterwards...hmm
Got the car good and warm then crawled underneath last night and viola, the #5 plug boot was arcing to the header tube (couldn't see it from above).
Pulled the header, dimpled the tube, replaced the boot (plug was ok), doubled up on header gaskets, and no more miss fire.