E85 tuning help - car falls flat

tbaumann

Member
I have got an issue that I hope you can help me diagnose. Currently I have 80lb injectors and a Walbro 255lph pump a TT chip for e85. Have upgraded the return line to -6. The feed line is stock. I have an AEM boost controller. The car cuts out in 3rd gear at WOT. If I back off a little it will come back. I pulled the tank to check things and upgraded the pump to a DW301. I tried it after the pump upgrade and same issue. The cuts out at WOT and falls flat. I have a scanmaster and the O2s start dropping at WOT from 800 to 700s and so on.

What are the next steps in problem solving using the scanmaster. I have read it could be a number of issues, coil pack, cam sensor, MAF, plugs... Is there a logical progression. I don’t want to throw money at parts hoping something will work.
 
Time to put a fuel pressure gauge on the car and get a powerlogger and wb for some data

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Agreed. If your going to run e85 in a car that isn't designed to do so, you're going to need more than a Scanmaster and narrowband.


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How much boost? Does it cut out in 1st and second gear at wot?
It seems to run good in 1st and 2nd. It will boost up to around 19 to 20 lb but drops off. I have a fuel pressure gauge I will relocate it to windshield and take some reading during a pull. I will also try to see exactly when the boost drops off. Are there any other readings that might help. No power logger yet.
 
How much boost? Does it cut out in 1st and second gear at wot?
OK here is the latest. I did some test runs last night and monitored the fuel pressure via a gauge on the winshield. The fuel pressure seems to be moving up with boost 1 to 1. I did a run with the AEM boost controller switched off which should use the factory waste gate. The WG is set to 16 lbs via a shortened rod. The issue of the car falling down is still there. I dont notice it in 1st, but it will do it in 2nd and 3rd at WOT. If I back out of it to say 80 % throttle, the car will come back. This only seems to happen at WOT.
I really appriciate the help and experience of the fourm - Thanks.
 
What kind of timing are u runing I've noticed with my car that I needed to put at least 3* more in my whole spark table or else it would fall flat on its face as u r describing .
 
OK here is the latest. I did some test runs last night and monitored the fuel pressure via a gauge on the winshield. The fuel pressure seems to be moving up with boost 1 to 1. I did a run with the AEM boost controller switched off which should use the factory waste gate. The WG is set to 16 lbs via a shortened rod. The issue of the car falling down is still there. I dont notice it in 1st, but it will do it in 2nd and 3rd at WOT. If I back out of it to say 80 % throttle, the car will come back. This only seems to happen at WOT.
I really appriciate the help and experience of the fourm - Thanks.
Check plug gap ..
 
Did some checking on the chip for timing. It is a 5.6 TT from Eric setup for 80s running at 23lbs and 24 - 23 degrees of timing default.
Not sure on the age of the value springs but the car seems to behave this way at 16lbs or 20 lbs.
The plugs are NGKs gaped at about 30 to 35 if i remember. I will need to double check the plugs.
 
Did some checking on the chip for timing. It is a 5.6 TT from Eric setup for 80s running at 23lbs and 24 - 23 degrees of timing default.
Not sure on the age of the value springs but the car seems to behave this way at 16lbs or 20 lbs.
The plugs are NGKs gaped at about 30 to 35 if i remember. I will need to double check the plugs.

If they are gapped that big.. You need to tighten that up .035 is way way too much gap
 
what turbo89 said....could be blowing out the spark with that much gap once boost increases.

I'd tighten up the gap to no more than .028 tops.
 
Do the simple stuff first like check your plugs and close those gaps to see if the condition improves. If not, next place I would look is the coilpack and module.
 
Do the simple stuff first like check your plugs and close those gaps to see if the condition improves. If not, next place I would look is the coilpack and module.
The latest = I gapped the plugs to 27 and the car seem to be much better. I took the car out later in the evening and it was acting up again. The only difference was the temperature dropped 10 to 15 degrees. I am thinking of doing the coil next. Maybe a HO coil pack. Any recommendations on the coil pack. I might also tighten up the a bit more.
 
If your ignition system is up to par you shouldn't have to go tighter than .27 with 23lbs of boost on your setup. If the condition improves by closing the gap that could be a hint your ignition system is suspect. The coil pack and module should be changed out as a set. Short of switching over to a TR6 setup, imo the best module to get is a second generation genuine AC Delco module (made by Magnavox). Some have success running aftermarket modules while others not so much. I've not heard of anyone having problems with a properly working Magnavox unit unless the unit itself is bad to begin with. The only problem is finding one and they are not cheap... HighwayStars sells a coil pack for $49.95 that works great. This is the one I am currently using. The only issue with it is it doesn't test well with the Caspers Ignition Simulator. But if you don't have one anyway then its a non-issue.

Even if it doesn't solve your problem, after going through my share of ignition related issues I always have a known good coil pack & module as a backup for testing purposes. Chances are sooner or later you're going to need it. If you need help locating an AC Delco module let me know.

If you're still running a stock MAF those are notorious for being flaky and should be another area to look into.
 
If your ignition system is up to par you shouldn't have to go tighter than .27 with 23lbs of boost on your setup. If the condition improves by closing the gap that could be a hint your ignition system is suspect. The coil pack and module should be changed out as a set. Short of switching over to a TR6 setup, imo the best module to get is a second generation genuine AC Delco module (made by Magnavox). Some have success running aftermarket modules while others not so much. I've not heard of anyone having problems with a properly working Magnavox unit unless the unit itself is bad to begin with. The only problem is finding one and they are not cheap... HighwayStars sells a coil pack for $49.95 that works great. This is the one I am currently using. The only issue with it is it doesn't test well with the Caspers Ignition Simulator. But if you don't have one anyway then its a non-issue.

Even if it doesn't solve your problem, after going through my share of ignition related issues I always have a known good coil pack & module as a backup for testing purposes. Chances are sooner or later you're going to need it. If you need help locating an AC Delco module let me know.

If you're still running a stock MAF those are notorious for being flaky and should be another area to look into.
Thanks for all of the help. I really appreciate it. I up'd my base fuel pressure to 43( with the line on) when I gaped the plugs. I will look into HighwayStars coil pack. I will do some researching for a module.

I believe the MAF is stock - What is the best option for a MAF?
Again thanks again for the all of the help.
 
Thanks for all of the help. I really appreciate it. I up'd my base fuel pressure to 43( with the line on) when I gaped the plugs. I will look into HighwayStars coil pack. I will do some researching for a module.

I believe the MAF is stock - What is the best option for a MAF?
Again thanks again for the all of the help.
Try starting at 43psi line off and see what happens.

Popular option for a MAF is get a Translator and switch to a LS1 (preferable) or LT1. Try to avoid the aftermarket stock type MAF if possible. If you need a known good stock MAF and/or module let me know maybe we can work something out.
 
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Try starting at 43psi line off and see what happens.

Best option for a MAF is get a Translator and switch to a LS1 (preferable) or LT1. Try to avoid the aftermarket stock type MAF if possible. If you need a known good stock MAF and/or module let me know maybe we can work something out.
I tried the pressure at 43 line off but it seems to respond better with higher pressure. I will need some advice on an ignition Module. I see that Kirban and Highway Star have them.
What is folks advice on the MAF ??
 
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