T76 60# mototrons at fault?
06-15-2008, 12:59 PM
#1
T76 60# mototrons at fault? Anyone have some 30 to 4x pound injectors laying around in good working order?
I'm using a custom PCM4Less Turbo Tune I purchased from Bryan Herter.
I'm trying to get my motor figured out and after reflashing the tune literally 25 times to tweak this and that, it still runs like crap. It now has the original PCM4Less tune intact, installed. The 4 cylinder rental car I just turned in yesterday could smoke me in any racing venue, 1/8th mile, 1/4mile, you name it. It's not the turbo setup. It runs like exrement from idle on up, even with the turbo disconnected and just running Normally aspirated. So in a process of elimination, I wanted to swap out the 60# mototrons and put in a known good set of smaller injectors. I bought these mototrons used and I don't know if they have issues or not. I've checked the rocker arms, the plugs (all showing rich). I've checked the AFR with my wide band and it shows a tad rich at 13.1. If the injectors don't fix it, then I'll start replacing the LS1 coils to see if one of them is bad. It is really weak in power. Almost like it's running on 6 cylinders. A couple of times I've edged up into the boost of 1 or 2 pounds but that just makes it run even worse.
What it does is buck and run very unevenly.
I'm using a custom PCM4Less Turbo Tune I purchased from Bryan Herter.
I'm trying to get my motor figured out and after reflashing the tune literally 25 times to tweak this and that, it still runs like crap. It now has the original PCM4Less tune intact, installed. The 4 cylinder rental car I just turned in yesterday could smoke me in any racing venue, 1/8th mile, 1/4mile, you name it. It's not the turbo setup. It runs like exrement from idle on up, even with the turbo disconnected and just running Normally aspirated. So in a process of elimination, I wanted to swap out the 60# mototrons and put in a known good set of smaller injectors. I bought these mototrons used and I don't know if they have issues or not. I've checked the rocker arms, the plugs (all showing rich). I've checked the AFR with my wide band and it shows a tad rich at 13.1. If the injectors don't fix it, then I'll start replacing the LS1 coils to see if one of them is bad. It is really weak in power. Almost like it's running on 6 cylinders. A couple of times I've edged up into the boost of 1 or 2 pounds but that just makes it run even worse.
What it does is buck and run very unevenly.
06-15-2008, 04:35 PM
#2
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Under load is the AFR 13.0:1? If so, it needs to be 11.5:1.
Most mail order tunes will get you in the ballpark but it allways needs checked on a dyno while datalogging for knock and everything else.
If it has been ran for a while under boost being lean, you may have either burnt it up, or rattled it and broke a piston. If this is the case, do a compression/leakdown test to verify integrity.
Most mail order tunes will get you in the ballpark but it allways needs checked on a dyno while datalogging for knock and everything else.
If it has been ran for a while under boost being lean, you may have either burnt it up, or rattled it and broke a piston. If this is the case, do a compression/leakdown test to verify integrity.
06-15-2008, 05:37 PM
#4
Sorry. I should have provided context. The 13:1 is at idle. I haven't been into boost of more that 1psi and that was for less than a second. Like I said, it runs like crap even with the Turbo discharge disconnected from the Throttle body. I just went and picked up some new coils(LS1 coils on an LTCC ignition) and some smaller, known to be good, injectors to try to trouble shoot this. Thanks for the responses 
06-15-2008, 08:00 PM
#6
Yes. I'm running speed density/Open loop right now. I pulled the plugs back last Thursday after getting the car off the transport. After going over to my buds house with the old plugs we were discussing how one of them looked notably cleaner than the other seven and wet. ?!! We discussed this revelation and he lent me one of his sets of coils off one of his LS1 Fbodies to test the coils as well. (You may know him. His name is Brian Grimal). Seeing how testing coils is much easier than swapping injectors, I crossed my fingers and swapped the drivers side coil set first. Right off the bat, it started with more authority and idled smoother. I thought "Wow! It's ignition coils?". So I decided to take a quick drive. It was so much better but after about a block it was obvious, it's running on 7 cylinders. Holy crap! In one of my earlier posts I'd mentioned that previous to this, it felt like it was running on 6. It must have been! So, encouraged but puzzled, I drove back to the garage and swapped on the other sides coil set. Took a drive. Bah.. still on 7. And I mean it is a DEAD cylinder, whichever one it is. It doesn't occasionally hit. It's missing in action/AWOL completely. So back to the garage. I'm letting it cool down now. I'm going to pull the plugs again and have a look at them. I'm hoping one of them on the drivers side is totally fouled and all it will take is a new set of plugs. After I pull them, I'll lay them across the top of the valve covers, turn on the key and spin the motor over with my remote starter button to see if they spark or not.
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06-16-2008, 10:08 AM
#11
The flash I'm running right now utilizes Open Loop only. The MAF Grams is normal, the Map is 45ish, the right O2 sensor shows low 9xx. The advance is 32 at idle. Pulsewidths are 2.18 at idle. With my wide band hooked up to the right side, the AFR shows to be 13.1, a tad rich for idle.
During driving, it is weak. If I press the gas pedal even a little to go from say like 30mph to 35mph, the car bucks, not backfiring. Infrequently, I can feel it hits on one of the errant cylinders.
During driving, it is weak. If I press the gas pedal even a little to go from say like 30mph to 35mph, the car bucks, not backfiring. Infrequently, I can feel it hits on one of the errant cylinders.
06-16-2008, 10:10 AM
#13
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Just use a spray bottle with some water in it and spray the header/ manifold at the port exit while running. The dead cylinder, the water will run off, the good, it turns to vapor in an instant.
I would back the timing back to 20-22 at idle, and it seems that idle pulse width is high. I use 60's a lot and they all idle at around 1.7-1.8 ms.... at around 14.5 to 1.
The other problem, with no transition /no power sounds like fuel delivery to me, not ignition. What is the fp, and what do you have in your ve table?
I would back the timing back to 20-22 at idle, and it seems that idle pulse width is high. I use 60's a lot and they all idle at around 1.7-1.8 ms.... at around 14.5 to 1.
The other problem, with no transition /no power sounds like fuel delivery to me, not ignition. What is the fp, and what do you have in your ve table?
06-16-2008, 10:10 AM
#14
It's tough getting this going. I pulled 3 of the easiest to access left side plugs this morning and I thought one looked especially poor. I hooked them up on top of the intake and cranked the motor. One's spark was barely there and I thought I had the culprit. I pulled one of my other old plugs from the shelf and put it in and headed off to Advanced Auto to get a new set of plugs. It went downhill from there. Once again, it was stumbling along on 6 cylinders (if that). I got the plugs and, of course, some damned Subby WRX sees my intercooler grinning in the front and he thinks he's going to test my traction. At every light, I can barely take it off and keep the motor alive and the Subby rushes up on my *ss waiting for me to take off. Lol... good grief. I pulled the car into the garage and I have the fan on it, cooling her down before pulling the crossover, intermediate pipe then the plugs to replace them. I'm going to go ahead and swap the injectors to some 28# that I borrowed. I need to get the car running so I can get to/from work. I'll address the higher HP stuff later.
06-16-2008, 10:55 AM
#16
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If you want to check which cylinders are firing, and get either remove a plug lead, or unplug the coil....unplug each injector in turn and listen for an rpm change.
To test for a spark, remove the plug lead and stick your finger in the end then start the engine
Ignore that last comment
To test for a spark, remove the plug lead and stick your finger in the end then start the engine
Ignore that last comment
06-16-2008, 11:26 AM
#17
I tried a variation of that yesterday. I pulled 4 plug wires in turn and the difference was astonishingly near non existent. I was hoping for something pronounced but it's running so crappy right now, it's hard to discern a slight difference. Thanks for the suggestion.
If you want to check which cylinders are firing, and get either remove a plug lead, or unplug the coil....unplug each injector in turn and listen for an rpm change.
To test for a spark, remove the plug lead and stick your finger in the end then start the engine
Ignore that last comment
To test for a spark, remove the plug lead and stick your finger in the end then start the engine
Ignore that last comment
06-16-2008, 06:17 PM
#19
As it is, it's running on 6 cylinders. Jeez.. this thing is kicking my *ss. Let me state what hardware I started out with last week..
Completely new forged shortblock put together by a guy that builds several of these for race cars.
New LTCC ignition system (still uses my stock Opti which was working fine), used set of Ls1 coils
Used 60# mototrons.
New Bret Bauer Cam kit
New Comp Cams lifters
New spark plugs
New plug wires
New pushrods
Prior Ported Lt1 heads
Custom Turbo tune by Bryan Herter of PCM4less.
=============================
Here's what I've changed in an effort to pin down what is making it miss on at least two cylinders.
2 new O2 sensors - result = no improvement
2 new sets of plugs - result = no improvement
Gone from Brians tune to a stock one and back in 29 reflashes to date-Result = occasional improvement in idle. Still misses when driving
Replaced all the Ls1 coils with ones from a working LS1 - result = No improvement.
Replaced the 60# mototrons with 28# from a buds LS1 - result = No improvement.
Rechecked the valve lash on the drivers side head. - = Result No improvement.
Took all the plugs out on the drivers side and laid the plug from that cylinder, using IT's own plug wire, on the valve cover. Cranked it over, they sparked just fine.
The last time I pulled the plugs, all the passenger side looked good, which is what the scanner was showing for O2 readings. The problematic drivers side had plugs that looked like the passenger side (clean) on cylinders 3 and 7. Cylinders 1 and 5 looked fouled. Given this revelation, I went and picked up new spark plugs and put them in. As SOON as I cranked it over, it was missing the very same way it was before I swapped the plugs! Thats when I swapped injectors. Imagine my disgust when after finishing that, reloading the turbo tune with the new injector constant, firing it up, as soon as it fired up, it misses the very same way. After getting it started and idling roughly, I went out to shake the wiring harness on the LTCC and coils to see if I had a wayward connection. No luck(except bad of course, lol)
I just called a rental place to rent another farking rental for a few weeks till I get this figured out. It's just sooooo weird!!! The passenger side is fine! It's getting fuel. It's getting spark. The valves were going up and down correctly when I was adjusting the valves. I can't think of what else it could be.
Completely new forged shortblock put together by a guy that builds several of these for race cars.
New LTCC ignition system (still uses my stock Opti which was working fine), used set of Ls1 coils
Used 60# mototrons.
New Bret Bauer Cam kit
New Comp Cams lifters
New spark plugs
New plug wires
New pushrods
Prior Ported Lt1 heads
Custom Turbo tune by Bryan Herter of PCM4less.
=============================
Here's what I've changed in an effort to pin down what is making it miss on at least two cylinders.
2 new O2 sensors - result = no improvement
2 new sets of plugs - result = no improvement
Gone from Brians tune to a stock one and back in 29 reflashes to date-Result = occasional improvement in idle. Still misses when driving
Replaced all the Ls1 coils with ones from a working LS1 - result = No improvement.
Replaced the 60# mototrons with 28# from a buds LS1 - result = No improvement.
Rechecked the valve lash on the drivers side head. - = Result No improvement.
Took all the plugs out on the drivers side and laid the plug from that cylinder, using IT's own plug wire, on the valve cover. Cranked it over, they sparked just fine.
The last time I pulled the plugs, all the passenger side looked good, which is what the scanner was showing for O2 readings. The problematic drivers side had plugs that looked like the passenger side (clean) on cylinders 3 and 7. Cylinders 1 and 5 looked fouled. Given this revelation, I went and picked up new spark plugs and put them in. As SOON as I cranked it over, it was missing the very same way it was before I swapped the plugs! Thats when I swapped injectors. Imagine my disgust when after finishing that, reloading the turbo tune with the new injector constant, firing it up, as soon as it fired up, it misses the very same way. After getting it started and idling roughly, I went out to shake the wiring harness on the LTCC and coils to see if I had a wayward connection. No luck(except bad of course, lol)
I just called a rental place to rent another farking rental for a few weeks till I get this figured out. It's just sooooo weird!!! The passenger side is fine! It's getting fuel. It's getting spark. The valves were going up and down correctly when I was adjusting the valves. I can't think of what else it could be.