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So a customer drops his car off for an AEM tune

9K views 68 replies 29 participants last post by  Import Power 
#1 ·
Another shop had "tuned" it but it was running very poorly and could not get over 16psi with out breaking up and just over all running bad. Bad idle that is high, then low, then surges up and down, etc etc.

I will spend some time on it later, building a new map from scratch of course, I never trust another shops map and won't build off of it cause you never know what small detail you will miss on one of the buried graphs etc. But like looking into what was "tuned" at this point and why it may be running poorly.

But here is what I found in 5 minutes looking at it.

92 RTTT
Forged rods and pistons
Forged crank
JDPC TD05 kit
MHI EVOIIIs
Walbro pump
680 PTE
AEM Meth kit
boostaspark
etc

I like to shoot for pump gas (on TD05) 20 degrees at redline at 20psi. It's a good benchmark to kinda aim for.

This AEM was setup with 9 degrees at 20psi at redline. Wow, that's low.

Then I thought, Let me check the base timing. This needs to be set before anything else to ensure when the AEM puts out 15 degrees, the engine will actually be at 15 degrees.

Sure enough, when the car is at idle and the AEM is putting out 15 degrees, the actual mechanical timing on the car is.......5

So at 20psi at redline the car is somewhere around 0 to -1 degrees.

Knock control is set maxed out at 1.4 volts. Very conservative.
Oh wait, if it were turned on. Yep, it's unchecked, it's off.

Looked around for a few more minutes and found some other funny things. Can't wait to dig in and tune her up!

-Chris
 
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#41 ·
Yeah, certs mean nothing. I learned that back when I was getting my MCSE certs. But it was after being in computers for over a decade.

Then being in the field, and watching employers pass over experience for no experience "certified" people. It was fun watching them with a real world problem and scrambling for books and such to figure it out. And still not getting the solution, then I or another experienced person would go and fix the issue in 5 minutes.

Paper certifications, they are a joke. I know "master techs" who can't put gas in their car. They just knew how to remember how ASE wanted the questions answered....but really didn't understand WHY that was the answer. It's sad.

So many hacks out there. What erks me is the customer then pays big money to get screwed over, when they make it to me or another good tech, they are out of money or don't feel they should pay again. Luckily I don't ream customers like some shops do.

Here is the "hotwire kit install"



Here it is fixed:



-Chris
 
#42 ·
Another day of fun. No really, I love this stuff. I must be a sadomasochist.

After all the fixes yesterday I thought she would be ready for a full clean 16psi run. I'm funny aren't I. Still breaking up. And I knew exactly what it was.

So I test the ignition system. Very weak spark, no energy at all. But the customer had said the coils and ptu were new. Coils looked new....but NOT OEM. Just like other parts I swear by and ALWAYS tell customers or anyone that is looking for advice, Coils and PTU need to be OEM. Period. End of story.

So today's lesson is brought to you by the letter "C"



So, new OEM coils and PTU (I always swap out as a set, I have seen one take out the other)

And here is the new 16ish run, versus the original when dropped off. Still a little tuning, it hovers around 11.0 then down to 10.8 around 5250. But the AFR line is pretty smooth. And yeah, before it felt slower than my Corrolla, not anymore! It hauls pretty damn well. Still more boost and timing to add, still very quiet knock volts.



-Chris
 
#46 ·
#49 ·
Now you get it. BAD copies of everything.

I also never take a customer at their word. But I do take the info from their tales. Yeah its a new part and didnt fix the problem. Thats because the NEW part caused ANOTHER problem!

Go Chris! I'm glad fixing that car has actually been easier than I thought it would when you started this thread.

-SP
 
#55 ·
Real Talk!

When I was installing my twin 400 pumps, my sender looked like a dirt/rust hat on top of my gas tank- all the wiring and terminals were corroded to balls

Nothing a wire brush, and some plastic media blasting couldn't take care of- though the terminals needed to be redone with gromits and new wires completely as the wiring was corroding off the top of the hat and causing iffy voltage to my fuel pumps.....

Northern salt sucks.......as do the occaisional -20/-30 temps in the dead of winter.
 
#50 ·
Changed the oil and did a little more tuning today. Got her up to 18-19psi. AFR is looking real good and smooth.

When dropped off she could not do more than 13-14psi and sometimes 8psi due to all the issues. They are fixed and she pulls had and smooth.

I need to rest a bit, too much too many days in a row. But in a few I will turn on his METH and see if it likes 20psi.

Here is the initial run in blue (the way the customer dropped it off) versus the last pull today in red.



-Chris
 
#52 ·
Engine is getting noisy and the meth injection doesn't help and timing is in line. And since I didn't build the engine I am not going to push it.

Graph is a little more shaky than previous as I made the JPG of it with smoothing at 1 instead of 2 like I did previous.

18psi 498HP and pulls real nice and hard and smooth.



-Chris
 
#57 ·
Video of customer reaction during first drive needed! :D
 
#59 ·
OK,

Reinstalled the boostaspark, and reinstalled the AEM Water/Meth kit. It was installed with the tank in the hatch and the pump in the engine bay which is a no no. Plus the pump was higher than the tank, another no no. Plus the wiring was done with single strand housewire (as was he boostaspark),wire nuts, scotch locks, and the ignition/on power wire was dead.

Got is all installed correctly, tank in hatch with pump right next to it lower than fluid level at the fluids lowest level. Primed/tested with no nozzle/jet attached. Pink **** was coming out of the line. Got that all purged out. Checked he steel mesh screen on the nozzle/jet and it was totally covered/clogged with some pink ****. Cleaned that. Put nozzle/jet on the line and tested, a nice fine mist. Check.

Tuned it until the fuel pump ran out. No matter what I tune for anything past 20psi she runs out of fuel. PTE 680s with correct base pressure and Walbro 255LPH HP with Ninja Performance hot wire kit that I installed. It's just out of fuel. So I backed it down to 18psi for safety. Has a nice smooth and long power band. No knock and I leaned towards conservative on the knock cal table. Then again, there are no spikes on knock volts or knock raw. Quiet as a mouse.

Here is the final running 18 psi pull.



-Chris
 
#60 ·
Here is the final running 18 psi pull.



-Chris
So you lost a little HP but gained around 50Ft\Lb's of torque.

I was looking at Trevor's fuel injection sizing data and it seems 680's would be able to handle more HP with higher fuel pressure.

I am assuming it is a fuel pump issue?

Your thoughts.
 
#64 ·
He had a boostapump in a box, and I coulda hooked it up, but

1. I am fine with crutching a pump a little, but when a pump is out of steam and the crutch is all that is allowing it to do what it needs it worries me, time for more pump

2. the brakes (and suspension and other things) on this car are scary to stop the car at 30mph, it was getting 100% irresponsible to do any more until I find a dyno.

The customer wants to have the brakes done later and wants more power and is willing to put in the Walbro 400lph pump later so....

-Chris
 
#63 · (Edited)
Throw in a walbro 400 and keep going:)

Why did the weight change 100lbs from the last VD graph? Dead body, anchor, prostitute, supermodel, justin bieber?

edit: good work by the way. It is hitting 400 and 500 tq at the exact points my 3.5, 10:1, e85 car did in VD. I do need to actually check my car's weight though. Think it may be heavier than I estimated because of the added weight of 4" fmic, 6g74, etc vs the weight I pulled. Also, out of boost (i.e. below 3k) I am actually less hp/tq but with more displacement, compression and e85 vs this car you are tuning.
 
#65 ·
Being a little more realistic. No weight loss has been done on the car, there is a full stereo system with two large amps, deep cycle yellow top, cap, and 19" almost full face no name chrome rims that weigh tons. It's probably even heavier.

-Chris
 
#68 ·
Yep, anything in the 20+psi range she would start to lean out in the upper RPM range no matter how much fuel I added. Flat out from tq peak and even higher than tq peak, she would lean out at high RPM. Lower to 18-19psi and all is golden. Did this back to back to back to back to make sure. Need to just get a pressure sensor, I have the gauge adapters that go on the fuel rail. Could just hook up the sensor and log it. But my results were pretty conclusive.

-Chris
 
#67 ·
Chris, sounds like the new weight is more accurate. If you changed the weight back to previous you would be making a little less hp than before, correct? You back off the tune a little to keep it safe for owner?

Nom, updated my build thread last night. Yep, PM me about what you have going on with your cams.




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#69 ·
20psi was the breakpoint for the fuel, so I eeked her back to 18psi and took a degree of timing out and made this last run. Dead quiet and great AF line.

-Chris
 
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