Some gas analyzer data
09-11-2005, 05:52 PM
#51
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Yeah, I posted on the Southern California Area section of this site asking about TPI's for borrowing from people in my area. One guy actually lives about 10 minutes from my house and has a manifold. I'll probably do it pretty soon... But geez, I'd hate to think that this problem is so insurmmountable that I'd have to ditch the manifold.
09-11-2005, 07:15 PM
#52
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Car: An Ol Buick
Engine: Vsick
Transmission: Janis Tranny Yank Converter
Originally posted by dimented24x7
Rebuilt the entire distributer, spent lots of money, did lots of diagnostics, and in the end realized that the entire problem was due to a greasy dist. base blocking the ground path.
Rebuilt the entire distributer, spent lots of money, did lots of diagnostics, and in the end realized that the entire problem was due to a greasy dist. base blocking the ground path.
Wellll, one day I innocently changed plugs, and the car developed a miss. I changed everything, I could, overhauled the carb (remember those?), and spent 2 days trying to figure out what I'd done wrong. Tried the old plugs, everything. It got to the stage of replacing the plugs with the 4th set, that I finally smeared enough never sieze around to figure out that I had too much never sieze on, and that was making for a poor ground for the plug.
Somehow wasting a couple days with that one, was kind of a learning experience.......
09-11-2005, 08:58 PM
#53
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Thread Starter
Originally posted by Grumpy
overhauled the carb (remember those?),
overhauled the carb (remember those?),
Originally posted by Grumpy
figure out that I had too much never sieze on, and that was making for a poor ground for the plug.
figure out that I had too much never sieze on, and that was making for a poor ground for the plug.
09-11-2005, 10:41 PM
#54
Supreme Member
Thread Starter
Grumpy, good thought, but unfortunately that wasn't it.
I ohmed out the grounds on the plugs with respect to the (-) battery terminal, and all of them were under 500 milliohms. But, to be sure, I cleaned off all the threads and got into the plug holes on the heads with a small wire brush and cleaned them out as well. Fired up the car, and still the same rough idle.
I ohmed out the grounds on the plugs with respect to the (-) battery terminal, and all of them were under 500 milliohms. But, to be sure, I cleaned off all the threads and got into the plug holes on the heads with a small wire brush and cleaned them out as well. Fired up the car, and still the same rough idle.
09-12-2005, 02:22 AM
#55
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Car: Z28
Engine: L98
Transmission: T56
Yeah, that miniram is an expensive chunk of metal, so I guess I'd be a little upset too.
On the other hand, at least you can eliminate it as a source of the problem, or maybe solve the problem? Who knows. A little process of elimination, a little "eliminate everything, and whatever else is left must be the cause".
My opinion (and we all know about those) is that the miniram is not suited to that mild of a motor anyways. a holley stealth ram would be more appropriate..or even an accel/lingenfelter superram. but the HSR is easier to work on/around. But anyways --
A few other random ideas.
Have you had a valve cover off and watched the valvetrain while the engine was running? it's going to make an oily mess, but there is really no substitute for visual inspection.
How about getting a few different heat range plugs for cyl #2? maybe something 3 heat ranges colder, and also 3 heat ranges hotter. Try them both and see if there is any difference.
I think it's been mentioned before, but any spark crossover/spark jumping wires? Find a nice dark place, at night, and look under the hood with the engine running. Need darkness to inspect the entire HV system
use a timing light on #2. Your balancer may not be marked that far out, but at the very least you'll be able to make sure that the spark is occuring at the same spot on the balancer every time around, and you'll also be able to detect any erratic spark issues. Not as good as a spark scope, but it's free.
rig up a grounded 9th spark plug somewhere you can see the gap. hook #2 wire to this plug and run engine, observe spark quality. try the test plug on another cylinder or two for comparison sake.
if you have any way to beg/borrow/steal different sized injectors than what you are running, swap them into #2 and see what happens. If you are running 24# injectors, try a 28 in the #2 hole just to see if it responds. this will help determine if it's simply an air-fuel ratio problem in that hole. If it does respond then that will tell you if that hole really is lean for some reason, and if it doesn't respond (or gets worse) then you know it's a compression or spark issue.
plugged /crushed header tube on #2 and it just can't breathe? (maybe under the car near the collector, hit something?)
Have you ever loaded up new plugs in #2 and at least one other hole, started it and let it idle for 2-3 seconds while its missing, shut it down and pulled the new plugs for inspection? Does #2 still look perfect in that scenario?
One other comment...Since you've been dealing with this for two years now, it may be worth spending the weekend to yank the motor and do a good inspection - check ring end gap, measure ring thickness, check piston fit, deck height on #2, stuff like that. For example - purely speculative and probably absurd, but I could almost imagine a scenario where a rod could get slightly bent in a way that things still run OK, but the rod is effectively slightly shorter and the piston can't return to full TDC. This would result in a greatly reduced compression and a weak hole, especially at idle when there is more bleed down time to lose what compression did exist. speaking of - when you did your compression tests, did #2 build compression just as fast as the others? The common test is to crank the engine through three or four revs, and check pressure. BUt it might also be useful to know how much pressure is built on the first "hit"? For example: If #2 can only manage 60 or 70 on the first hit, and the rest manage 100, but after 3-4 "hits" they all come up to 160 or something, that could indicate somehow that #2 is a weak hole (less air moving ability) but yet still seals. You could check that just by pulling the head off, and an inspection/comparison of the cylinder walls MIGHT lend hints, if there is a problem in the ring package.
I know you've done compression tests and leakdown tests, but you still never know until you take it apart, eyeball it, and measure it. When Total Seal shipped me 1/16" rings for the #2 land in my pistons (when I needed 5/64), it was not caught during initial assembly and resulted in a smoking mother that was unsolvable yet passed all the normal tests (compression was great!), and it took dissassembling and a human eyeball to find the problem.
On the other hand, at least you can eliminate it as a source of the problem, or maybe solve the problem? Who knows. A little process of elimination, a little "eliminate everything, and whatever else is left must be the cause".
My opinion (and we all know about those) is that the miniram is not suited to that mild of a motor anyways. a holley stealth ram would be more appropriate..or even an accel/lingenfelter superram. but the HSR is easier to work on/around. But anyways --
A few other random ideas.
Have you had a valve cover off and watched the valvetrain while the engine was running? it's going to make an oily mess, but there is really no substitute for visual inspection.
How about getting a few different heat range plugs for cyl #2? maybe something 3 heat ranges colder, and also 3 heat ranges hotter. Try them both and see if there is any difference.
I think it's been mentioned before, but any spark crossover/spark jumping wires? Find a nice dark place, at night, and look under the hood with the engine running. Need darkness to inspect the entire HV system
use a timing light on #2. Your balancer may not be marked that far out, but at the very least you'll be able to make sure that the spark is occuring at the same spot on the balancer every time around, and you'll also be able to detect any erratic spark issues. Not as good as a spark scope, but it's free.
rig up a grounded 9th spark plug somewhere you can see the gap. hook #2 wire to this plug and run engine, observe spark quality. try the test plug on another cylinder or two for comparison sake.
if you have any way to beg/borrow/steal different sized injectors than what you are running, swap them into #2 and see what happens. If you are running 24# injectors, try a 28 in the #2 hole just to see if it responds. this will help determine if it's simply an air-fuel ratio problem in that hole. If it does respond then that will tell you if that hole really is lean for some reason, and if it doesn't respond (or gets worse) then you know it's a compression or spark issue.
plugged /crushed header tube on #2 and it just can't breathe? (maybe under the car near the collector, hit something?)
Have you ever loaded up new plugs in #2 and at least one other hole, started it and let it idle for 2-3 seconds while its missing, shut it down and pulled the new plugs for inspection? Does #2 still look perfect in that scenario?
One other comment...Since you've been dealing with this for two years now, it may be worth spending the weekend to yank the motor and do a good inspection - check ring end gap, measure ring thickness, check piston fit, deck height on #2, stuff like that. For example - purely speculative and probably absurd, but I could almost imagine a scenario where a rod could get slightly bent in a way that things still run OK, but the rod is effectively slightly shorter and the piston can't return to full TDC. This would result in a greatly reduced compression and a weak hole, especially at idle when there is more bleed down time to lose what compression did exist. speaking of - when you did your compression tests, did #2 build compression just as fast as the others? The common test is to crank the engine through three or four revs, and check pressure. BUt it might also be useful to know how much pressure is built on the first "hit"? For example: If #2 can only manage 60 or 70 on the first hit, and the rest manage 100, but after 3-4 "hits" they all come up to 160 or something, that could indicate somehow that #2 is a weak hole (less air moving ability) but yet still seals. You could check that just by pulling the head off, and an inspection/comparison of the cylinder walls MIGHT lend hints, if there is a problem in the ring package.
I know you've done compression tests and leakdown tests, but you still never know until you take it apart, eyeball it, and measure it. When Total Seal shipped me 1/16" rings for the #2 land in my pistons (when I needed 5/64), it was not caught during initial assembly and resulted in a smoking mother that was unsolvable yet passed all the normal tests (compression was great!), and it took dissassembling and a human eyeball to find the problem.
Originally posted by ULTM8Z
Yeah, I posted on the Southern California Area section of this site asking about TPI's for borrowing from people in my area. One guy actually lives about 10 minutes from my house and has a manifold. I'll probably do it pretty soon... But geez, I'd hate to think that this problem is so insurmmountable that I'd have to ditch the manifold.
Yeah, I posted on the Southern California Area section of this site asking about TPI's for borrowing from people in my area. One guy actually lives about 10 minutes from my house and has a manifold. I'll probably do it pretty soon... But geez, I'd hate to think that this problem is so insurmmountable that I'd have to ditch the manifold.
09-12-2005, 08:42 AM
#56
Supreme Member
Thread Starter
Answers in bold....
*****************************
My opinion (and we all know about those) is that the miniram is not suited to that mild of a motor anyways. a holley stealth ram would be more appropriate..or even an accel/lingenfelter superram. but the HSR is easier to work on/around. But anyways --
I would think an LT1 would end up having the same problem. Especially the non-sequential, speed density, early versions. They're even more mild engines than mine. Maybe there's something else to those motors that I don't know...
A few other random ideas.
Have you had a valve cover off and watched the valvetrain while the engine was running? it's going to make an oily mess, but there is really no substitute for visual inspection.
I assume you're just thinking about watching to make sure all valves are going up and down properly? I have seen them like this while doing rocker arm adjustments, but I didn't notice any thing out of the ordinary. I've also inspected all the valve springs thinking I had one that was broken or something, but they all seem fine.
How about getting a few different heat range plugs for cyl #2? maybe something 3 heat ranges colder, and also 3 heat ranges hotter. Try them both and see if there is any difference.
I have gone 1 range colder and hotter, but didn't notice anything different.
I think it's been mentioned before, but any spark crossover/spark jumping wires? Find a nice dark place, at night, and look under the hood with the engine running. Need darkness to inspect the entire HV system.
I did this the other night. Not so much as even the slightest blue flash. I'm running factory GM wires with Delco plugs and these boots seal up very nicely.
use a timing light on #2. Your balancer may not be marked that far out, but at the very least you'll be able to make sure that the spark is occuring at the same spot on the balancer every time around, and you'll also be able to detect any erratic spark issues. Not as good as a spark scope, but it's free.
haven't done this yet specifically with respect to a point on the balancer. THough I have put a timing light on the number two wire to make sure that current was indeed traveling down the wire consistently. The pulsation of the light was constant for any given engine speed. I took this to mean that the spark energy was reaching the plug adequately.
rig up a grounded 9th spark plug somewhere you can see the gap. hook #2 wire to this plug and run engine, observe spark quality. try the test plug on another cylinder or two for comparison sake.
I have a dedicated spark tester and it jumps the gap very strongly.
if you have any way to beg/borrow/steal different sized injectors than what you are running, swap them into #2 and see what happens. If you are running 24# injectors, try a 28 in the #2 hole just to see if it responds. this will help determine if it's simply an air-fuel ratio problem in that hole. If it does respond then that will tell you if that hole really is lean for some reason, and if it doesn't respond (or gets worse) then you know it's a compression or spark issue.
My brother has a set of 30lb Motorsport injectors that he has lying around. I put one on the #2 cylinder first and ran it, and then around the entire engine and ran it. Probably should have recorded some data, but I was trying to see if the rough idle/misfire would go away. It didn't.
plugged /crushed header tube on #2 and it just can't breathe? (maybe under the car near the collector, hit something?)
This is definitely not the case
Have you ever loaded up new plugs in #2 and at least one other hole, started it and let it idle for 2-3 seconds while its missing, shut it down and pulled the new plugs for inspection? Does #2 still look perfect in that scenario?
Haven't done this. Probably worth a shot though. Delco plugs are very inexpensive.
One other comment...Since you've been dealing with this for two years now, it may be worth spending the weekend to yank the motor and do a good inspection - check ring end gap, measure ring thickness, check piston fit, deck height on #2, stuff like that. For example - purely speculative and probably absurd, but I could almost imagine a scenario where a rod could get slightly bent in a way that things still run OK, but the rod is effectively slightly shorter and the piston can't return to full TDC. This would result in a greatly reduced compression and a weak hole, especially at idle when there is more bleed down time to lose what compression did exist. speaking of - when you did your compression tests, did #2 build compression just as fast as the others? The common test is to crank the engine through three or four revs, and check pressure. BUt it might also be useful to know how much pressure is built on the first "hit"? For example: If #2 can only manage 60 or 70 on the first hit, and the rest manage 100, but after 3-4 "hits" they all come up to 160 or something, that could indicate somehow that #2 is a weak hole (less air moving ability) but yet still seals. You could check that just by pulling the head off, and an inspection/comparison of the cylinder walls MIGHT lend hints, if there is a problem in the ring package.
I know you've done compression tests and leakdown tests, but you still never know until you take it apart, eyeball it, and measure it. When Total Seal shipped me 1/16" rings for the #2 land in my pistons (when I needed 5/64), it was not caught during initial assembly and resulted in a smoking mother that was unsolvable yet passed all the normal tests (compression was great!), and it took dissassembling and a human eyeball to find the problem.
Afraid I don't have the time to take the engine apart right now. Though, the "first hit" compression test is a worthwhile effort. I'll have to print this thread out and go down the list one by one. There are several good things to try.
*****************************
My opinion (and we all know about those) is that the miniram is not suited to that mild of a motor anyways. a holley stealth ram would be more appropriate..or even an accel/lingenfelter superram. but the HSR is easier to work on/around. But anyways --
I would think an LT1 would end up having the same problem. Especially the non-sequential, speed density, early versions. They're even more mild engines than mine. Maybe there's something else to those motors that I don't know...
A few other random ideas.
Have you had a valve cover off and watched the valvetrain while the engine was running? it's going to make an oily mess, but there is really no substitute for visual inspection.
I assume you're just thinking about watching to make sure all valves are going up and down properly? I have seen them like this while doing rocker arm adjustments, but I didn't notice any thing out of the ordinary. I've also inspected all the valve springs thinking I had one that was broken or something, but they all seem fine.
How about getting a few different heat range plugs for cyl #2? maybe something 3 heat ranges colder, and also 3 heat ranges hotter. Try them both and see if there is any difference.
I have gone 1 range colder and hotter, but didn't notice anything different.
I think it's been mentioned before, but any spark crossover/spark jumping wires? Find a nice dark place, at night, and look under the hood with the engine running. Need darkness to inspect the entire HV system.
I did this the other night. Not so much as even the slightest blue flash. I'm running factory GM wires with Delco plugs and these boots seal up very nicely.
use a timing light on #2. Your balancer may not be marked that far out, but at the very least you'll be able to make sure that the spark is occuring at the same spot on the balancer every time around, and you'll also be able to detect any erratic spark issues. Not as good as a spark scope, but it's free.
haven't done this yet specifically with respect to a point on the balancer. THough I have put a timing light on the number two wire to make sure that current was indeed traveling down the wire consistently. The pulsation of the light was constant for any given engine speed. I took this to mean that the spark energy was reaching the plug adequately.
rig up a grounded 9th spark plug somewhere you can see the gap. hook #2 wire to this plug and run engine, observe spark quality. try the test plug on another cylinder or two for comparison sake.
I have a dedicated spark tester and it jumps the gap very strongly.
if you have any way to beg/borrow/steal different sized injectors than what you are running, swap them into #2 and see what happens. If you are running 24# injectors, try a 28 in the #2 hole just to see if it responds. this will help determine if it's simply an air-fuel ratio problem in that hole. If it does respond then that will tell you if that hole really is lean for some reason, and if it doesn't respond (or gets worse) then you know it's a compression or spark issue.
My brother has a set of 30lb Motorsport injectors that he has lying around. I put one on the #2 cylinder first and ran it, and then around the entire engine and ran it. Probably should have recorded some data, but I was trying to see if the rough idle/misfire would go away. It didn't.
plugged /crushed header tube on #2 and it just can't breathe? (maybe under the car near the collector, hit something?)
This is definitely not the case
Have you ever loaded up new plugs in #2 and at least one other hole, started it and let it idle for 2-3 seconds while its missing, shut it down and pulled the new plugs for inspection? Does #2 still look perfect in that scenario?
Haven't done this. Probably worth a shot though. Delco plugs are very inexpensive.
One other comment...Since you've been dealing with this for two years now, it may be worth spending the weekend to yank the motor and do a good inspection - check ring end gap, measure ring thickness, check piston fit, deck height on #2, stuff like that. For example - purely speculative and probably absurd, but I could almost imagine a scenario where a rod could get slightly bent in a way that things still run OK, but the rod is effectively slightly shorter and the piston can't return to full TDC. This would result in a greatly reduced compression and a weak hole, especially at idle when there is more bleed down time to lose what compression did exist. speaking of - when you did your compression tests, did #2 build compression just as fast as the others? The common test is to crank the engine through three or four revs, and check pressure. BUt it might also be useful to know how much pressure is built on the first "hit"? For example: If #2 can only manage 60 or 70 on the first hit, and the rest manage 100, but after 3-4 "hits" they all come up to 160 or something, that could indicate somehow that #2 is a weak hole (less air moving ability) but yet still seals. You could check that just by pulling the head off, and an inspection/comparison of the cylinder walls MIGHT lend hints, if there is a problem in the ring package.
I know you've done compression tests and leakdown tests, but you still never know until you take it apart, eyeball it, and measure it. When Total Seal shipped me 1/16" rings for the #2 land in my pistons (when I needed 5/64), it was not caught during initial assembly and resulted in a smoking mother that was unsolvable yet passed all the normal tests (compression was great!), and it took dissassembling and a human eyeball to find the problem.
Afraid I don't have the time to take the engine apart right now. Though, the "first hit" compression test is a worthwhile effort. I'll have to print this thread out and go down the list one by one. There are several good things to try.
Last edited by ULTM8Z; 09-12-2005 at 08:44 AM.
09-12-2005, 08:49 AM
#57
09-12-2005, 12:55 PM
#58
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Car: Z28
Engine: L98
Transmission: T56
I'd agree on instinct, but experience with the 406 in my '71 tells me otherwise.
Total seal sent me 1/16 rings for one of my ring lands (I can't remember now if it was the top or middle, might have been the top, but irrespective..) and my KB hypereutectic pistons has 5/64 lands. great compression, great leakdown, but still burned a quart of oil every 45-50 miles. sure kept the mosquitos at bay, though. And it was a hard item to catch - we were pulling our hair out over this motor and just happened to notice by dumb luck the <i>second</i> time we pulled the motor that one set of rings was a bit looser than the others - the difference between 1/16 and 5/64 is only a few thousandths (12 if memory serves). Things that work well in a static, motionless test may not work well when running with all the changed dynamics that occur in a running engine.
thus i do believe it's possible to have rare/weird circumstances which test fine but still are wrong. they are at the bottom of my list of things to check, but when you've checked everything else multiple times over a two year period, well, the kooky mad science stuff has to be checked at some point too.
anyways, it all comes down to fuel, air, spark, and compression.
It seems like there has been enough work on the fuel system to rule it out for now. new injectors, wiring harness, etc.
ditto for ignition. the entire thing has been replaced from the distributor to the plugs and everything in between.
while I don't like the miniram, and it is known to have poor airflow distribution relative to other intakes, this intake has worked on his car previously, and I guess that can't be ignored. and I can't imagine an intake would "go bad".
so that leaves compression as the only item that we only have (basic) health testing of, and no parts have been replaced in that 'system'. After two years of parts swapping on every other system, it seems that an engine teardown is the way to go, regardless of any results of compression/leakdown tests. ignoring the harder answers doesn't always give you the answer.
I'm very curious to see what comes back from the "first hit' compression test. In a real running engine, you only get one chance per power stroke to build compression - not the 4-6 hits that typifies a compression check. for example, these results could be entirely possible (i'm making them up for example purposes) and would clearly indicate a problem in #2, despite a totally "normal" final compression:
cyl 1 -100 -125 -135 -140 -140
cyl 2 -050 -080 -105 -125 -140
cyl 3 -105 -130 -140 -140 -140
cyl 4 -095 -125 -135 -140 -145
etc.
I could think of a few possible causes - maybe a piston got damaged somehow, the skirt is knocked in a bit or the bore has opened up and it's just a weaker hole than the rest of them now. under static conditions the rings seal up fine, but under dynamic conditions, it's just moving around too much to seal effectively? Maybe the rings have weakened and the tension is all wrong - static testing probably woudln't reveal this, either.
you might call it grasping for straws, but after two years of troubleshooting and ideas with no solutions, seems like it might be worth it. certainly I didn't expect to find a problem with ring thickness in my motor, it's the kind of thing most would disregard, but it happened to me.
Total seal sent me 1/16 rings for one of my ring lands (I can't remember now if it was the top or middle, might have been the top, but irrespective..) and my KB hypereutectic pistons has 5/64 lands. great compression, great leakdown, but still burned a quart of oil every 45-50 miles. sure kept the mosquitos at bay, though. And it was a hard item to catch - we were pulling our hair out over this motor and just happened to notice by dumb luck the <i>second</i> time we pulled the motor that one set of rings was a bit looser than the others - the difference between 1/16 and 5/64 is only a few thousandths (12 if memory serves). Things that work well in a static, motionless test may not work well when running with all the changed dynamics that occur in a running engine.
thus i do believe it's possible to have rare/weird circumstances which test fine but still are wrong. they are at the bottom of my list of things to check, but when you've checked everything else multiple times over a two year period, well, the kooky mad science stuff has to be checked at some point too.
anyways, it all comes down to fuel, air, spark, and compression.
It seems like there has been enough work on the fuel system to rule it out for now. new injectors, wiring harness, etc.
ditto for ignition. the entire thing has been replaced from the distributor to the plugs and everything in between.
while I don't like the miniram, and it is known to have poor airflow distribution relative to other intakes, this intake has worked on his car previously, and I guess that can't be ignored. and I can't imagine an intake would "go bad".
so that leaves compression as the only item that we only have (basic) health testing of, and no parts have been replaced in that 'system'. After two years of parts swapping on every other system, it seems that an engine teardown is the way to go, regardless of any results of compression/leakdown tests. ignoring the harder answers doesn't always give you the answer.
I'm very curious to see what comes back from the "first hit' compression test. In a real running engine, you only get one chance per power stroke to build compression - not the 4-6 hits that typifies a compression check. for example, these results could be entirely possible (i'm making them up for example purposes) and would clearly indicate a problem in #2, despite a totally "normal" final compression:
cyl 1 -100 -125 -135 -140 -140
cyl 2 -050 -080 -105 -125 -140
cyl 3 -105 -130 -140 -140 -140
cyl 4 -095 -125 -135 -140 -145
etc.
I could think of a few possible causes - maybe a piston got damaged somehow, the skirt is knocked in a bit or the bore has opened up and it's just a weaker hole than the rest of them now. under static conditions the rings seal up fine, but under dynamic conditions, it's just moving around too much to seal effectively? Maybe the rings have weakened and the tension is all wrong - static testing probably woudln't reveal this, either.
you might call it grasping for straws, but after two years of troubleshooting and ideas with no solutions, seems like it might be worth it. certainly I didn't expect to find a problem with ring thickness in my motor, it's the kind of thing most would disregard, but it happened to me.
Originally posted by dimented24x7
I think a leakdown test would be good enough to rule out any engine problems.
I think a leakdown test would be good enough to rule out any engine problems.
Last edited by 91L98Z28; 09-12-2005 at 12:58 PM.
09-12-2005, 02:51 PM
#59
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Car: 91 Red Sled
Axle/Gears: 10bolt Richmond 3.73 Torsen
Get a carb, a carb fuel pressure regulator (3-port design preferably), a carb intake and bolt it on. See if the number 2 is still giving you issues. That should tell you if it's air/fuel or spark related.
09-12-2005, 03:36 PM
#60
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Car: 87 T/A
Engine: 441 SBC 12.5:1 0.680" Lift
Transmission: T-56
Axle/Gears: 4.10 TruTrac Moser 9"
Juggle some injectors, easy enough right?
Same on wires/plugs...
Same on wires/plugs...
09-12-2005, 03:59 PM
#61
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Car: Z28
Engine: L98
Transmission: T56
Great idea, and probably a lot simpler than swapping to a regular TPI intake and dealing with all the inherent plumbing issues.
that would instantly rule out the entire fuel injection system.
that would instantly rule out the entire fuel injection system.
Originally posted by JPrevost
Get a carb, a carb fuel pressure regulator (3-port design preferably), a carb intake and bolt it on. See if the number 2 is still giving you issues. That should tell you if it's air/fuel or spark related.
Get a carb, a carb fuel pressure regulator (3-port design preferably), a carb intake and bolt it on. See if the number 2 is still giving you issues. That should tell you if it's air/fuel or spark related.
09-12-2005, 06:10 PM
#62
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Originally posted by 91L98Z28
that would instantly rule out the entire fuel injection system.
that would instantly rule out the entire fuel injection system.
Though, I suppose it would rule out the long block as the problem. Thing is, it's just double the workload, because then I'd still have to put the TPI on just to rule out the MiniRam.
Swapping out to a TPI would rule out the long block, MiniRam, and EFI electronics/hardware all in one shot.
Just need to find the time to do it!
BTW, guys, wanted to say again that I really really appreciate all the patience, suggestions, and help you all have been in the last few years.
This has definitely been one for the books!! 
09-12-2005, 06:59 PM
#63
You could pressure test the miniram if you can't find a
TPI to use. Blank flanges requiring more work of course.
I could sell/loan you a LT1 if you want.
I'll give you a refund when you send it back.
TPI to use. Blank flanges requiring more work of course.
I could sell/loan you a LT1 if you want.
I'll give you a refund when you send it back.
09-12-2005, 09:08 PM
#64
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Car: 83 POS monte carlo 2015 chevy P/U
Engine: 92 5.7 tpi 5.3
Transmission: 700r4 6L60E
Axle/Gears: 2.42 too high
something to think about is a lifter pumping up, i have seen it happen & it can be a pain to pin down as it normally happens only while the motor is running, once you shut it down & get the gage in it bleeds down & is fine & everything looks good.
what type of compression gage do you have? does it have a bleed off valve that you can depress with it hooked up & the motor running? if it does, get the idle speed set to where the miss is & put the gage on a known good cylinder & start the motor up & hit the bleed valve & watch the gage a few times to see how a good cylinder builds compression with the motor running, then move it to your bad cylinder & see what it looks like.
be sure to unplug the injector & ground the plug wire before you start it up on the cylinder your looking at.
what type of compression gage do you have? does it have a bleed off valve that you can depress with it hooked up & the motor running? if it does, get the idle speed set to where the miss is & put the gage on a known good cylinder & start the motor up & hit the bleed valve & watch the gage a few times to see how a good cylinder builds compression with the motor running, then move it to your bad cylinder & see what it looks like.
be sure to unplug the injector & ground the plug wire before you start it up on the cylinder your looking at.
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