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Discussion Starter #1
Hey all, just figured I would share my results and continued issues. In May I had a Trick Flow top end kit with stg1 cam and 4" power pipe installed. At that time I also had the AC and smog removed. I had Bama send a tune for the combo so I could drive it back from the "mechanic". I didnt take it above 3k on the way home but I could tell there wasnt much there. It seemed like it actually lost power. I also had to stay on the gas to keep it running at stops which is a huge pain in Chicago traffic. I just had it Dyno tuned yesterday at DMARK performance in Arlington Heights and the results were huge. It actually pulls hard like it should and doesnt hang idle at 2k until I come to a stop. The numbers came out at 318/331 at the wheels and it was around 90 degrees in the shop so they may be a little better in cooler temps. I am very happy with it. It did not however fix my issue of dying out at idle. It will idle fine but it seems like the warmer it gets the more likely it is to flutter and then rev up and fall flat. I am pulling a 124 code for my TPS which is only several months old but also Duracraft brand. Aside from replacing that (what brand is OEM for TPS?) any other ideas? He did say my O2 sensors were acting a little wonky during the pulls.
1061669
1061670
 

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Discussion Starter #2
So here is where I am at now.

I went to drive it this morning and couldn't even get out of the garage without it dying. As soon as it went in gear and given a little gas it would just die as soon as I let off the gas.

The TPS I ordered came in, I got a Standard Motor brand one as it seemed closest to OEM as I could find. Put that in, set it. Drove around for a bit and it would idle fine at 1k. Every now and then it would surge a hair and drop down but level back to 1k. CEL came back on about 20 minutes into regular driving but still drove fine. 10 minutes or so later it started to hunt pretty heavy again so I aimed for home. It didn't die, but I was also actively trying not to. Also didn't feel quite as responsive as before but hard to tell.



Codes now are

124 still and 542 now.

Any ideas, suggestions?
 

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Set it?
The TPS is NOT adjustable.

Idle at 1,000 rpm??
That isn’t idle, it’s more closely to part throttle.

Have you been messing with the throttle stop? That will cause all of your problems. The idle is electronically controlled.
 

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Discussion Starter #4
Set it, adjusted it to .99. Its an aftermarket TB so it is adjustable. Part of the Dynotune was setting the throttle stop, timing, and fuel pressure and that was Thursday. He did mention the tach wasnt quite accurate, but what I am looking at shows 1,000 so that is what I relayed. I would rather not have to touch anything after the tune but I cant avoid traffic, stop lights or signs so I replaced the TPS since it had a code. Still has same code though.
 

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The throttle stop is not for setting the idle. If you paid the tuner to tune the idle, you should call them and complain.

Just curious, what did they tune the desired idle rpm for?

The TPS is not adjustable. Regardless of your aftermarket throttle body, the TPS is not adjustable. It’s only used as a reference point for closed throttle, the .99v is myth. It doesn’t have to be .99v, there’s an acceptable range to represent closed throttle. (But the throttle has to actually be shut so the IAC & EEC can do their job)

If the throttle stop has been cranked open, it’s allowing more air through than what the EEC expects, and the IAC closes to compensate along with the EEC altering spark advance to reach the target idle rpm.

P.S.- the fuel pressure shouldn’t be altered either unless you are using an aftermarket injector that is rated at a different fuel pressure, and those calibrations are changed in the tune.
Most people just use the 39.5 psi injectors.
 

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Discussion Starter #6
The tuner does initial setup of timing, throttle body angle, tps and fuel pressure before running it on the Dyno so he doesnt have to trust what I tell him it is set at. He did mention he can turn off the O2 sensors since he was seeing some funniness with them during the pulls. He also mentioned the possibility of a vacuum leak at load. He didnt mention what the RPM was tuned for. It doesnt seem like an overly fast idle where it is, when it drops lower it gets awfully shaky. I think we are are in agreement with the TPS whether or not I am correctly using the terms. I read in a number of threads .5-1.25 is fine. When I put it on it was 1.23 which while in range I still adjusted the TB so the TPS read .99-1.00 for a little more breathing room when I tightened it down. I am using 44lb injectors and a 255lb fuel pump. My MAF is set for those. Including relevant parts in case anything sticks out. It does seem to start to surge and stall once it heats up. It does not seem like my temp gauge is accurate after the top end was done so I would like to put in another sensor to see how hot it is actually getting.

Trick Flow Twisted Wedge 170 aluminum heads
Trick Flow Stage 1 cam
Trick Flow Track Heat Intake Manifold
BBK Shorty Headers
Offroad H Pipe
Flowmasters
Bosch 42lb/hr injectors
255lb/hr Wahlbro fuel pump
Adjustable Fuel Pressure Regulator
SR Performance 70mm Throttle Body
Anderson Power pipe
80mm Maf Calibrated for 42lb injectors
MSD 6AL Ignition Box
MSD Blaster Coil
Smog Delete
AC Delete
EGR Delete
Under drive pulleys
4:10 Gears
 

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You don’t need calibrated MAF meters with a proper tune.

The O2 sensors aren’t in operation during WOT pulls (Open Loop)

You can’t do a proper tune if you have a vacuum leak. It alters the air/fuel ratio.

I can tell you what the main problem with your car is, but you don’t want to hear it.
it’s the tune
 

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Discussion Starter #8
If its the tune I can take it back to him. He didnt do the work so I did have to have the calibrated MAF to get it out to him short of a tow. I am not sure why you say I dont want to hear it being the tune. That seems better than throwing parts at it. I would like to understand a little more just for my own curiosity if you are willing. Is there a material change in the tune parameters that it would drive ok/idle ok while cold and then what I assume is regular operating temp (20-25 minutes in 90 degree weather) and then getting worse the longer I drive it?
 

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Adaptive strategy.

You can unhook the battery for a while to allow the kam to be erased, then reconnect. It may be a better experience for you, until adaptive strategy starts correcting again.
 

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Discussion Starter #10
Oh well that seems like it would explain why it felt fixed right after I changed the TPS having unhooked the battery while I did the work. Would his suggestion of turning off the O2 sensors in the tune keep it in open loop and away from the adaptive strategy? (Terms could be way off so hopefully the idea is at least conveyed).
 

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I've been told by many 94-95 Mustang guys that for some reason the adaptive strategy for idle does not function correctly in the 94-95 computers when installing performance cams. They insist that it must be disabled in the tune to get these cars to idle without issues. Other tuners disagree. I had mail-order tunes done by Steve at Drag Radial Performance in Ocala FL. He did not disable the adaptive idle but only 1 out of 4 tunes on the SCT chip would idle properly even though he swore the idle parameters were all the same. The car made 280rwhp with GT40P heads and intake,Comp XE270 cam, 75mm tb/maf with 190lph pump, stock rails, 30# injectors, short headers, 2 1/2 exhaust and though an AODE with a 3k converter and 3.27 gears.

After switching cams it now acts the same as described here. @stampy167 I'll be watching this thread so keep it updated if you find a solution. I have the engine out now but was planning a dyno tune locally when I get it back in.

@HYBRED What do you say about the disabling of the adaptive idle?
 

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has the TPS code been fixed?

I dont think anybody knows the CBAZA better than Decipha at EFI tuning

I suggest you try that option
 

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Discussion Starter #13
No, so after changing out the TPS to a new standard motor product one, I still get the 124 code and am now seeing a 542 code. I just seen his name in a different thread now that I started searching adaptive idle. I can definitely look into that. Does he do SCT by mail or would it be time I finally got around to installing my megasquirt?
 

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As i suspected the sensor is NOT the issue, its the wiring

Forget any idea of removing this so called adaptive idle

contact Decipha, he will give the low down about what he requires for tuning

NOTE: it looks like you might have some serious wiring problems, you will need to straighten that out before any tuning

mega squirt is not going to fix anything with wiring
 

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Also, seriously consider getting rid of that aftermarket ignition

30 year old ford stuff, is far superior to that you have
 

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Discussion Starter #17
I had wanted to ask about that. I used the harness so it is easily reversible. Any chance that could be the cause of my woes? I imagine 25 year old wiring can get brittle but chasing that down sounds like a possible money pit unless I had the garage and skill to do it myself.
 

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Hybred explained very accurately what your problem is, no need to expand on that.

using the factory ignition, would be an upgrade from what you have, lets leave it at that.

As far as wiring, who knows the extent of what is needed

that is part of this hobby, often ignored but IMHO, the most important

if you are not up for it, sell, or find someone
 

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As has been said the tps needs to be functioning correctly for proper idle control.

if your o2's were acting up did yall replace them? The o2's are vital to properly dialing in the tune its imperative they function correctly. It is not wise to disable them.

if it idles fine then revs up on its own and then dies thats usually always from the tps freaking out. Same as with the cold conk out.

If you have a vac leak thats going to screw up idle as well.

As has been said the tps closed throttle position is saved as ratch at key on. The ecu uses that as a relative throttle position of 0 so the actual tps voltage isnt a concern so long as its not above 1.25 volts which is the stock value of RATIV that forces part throttle and youll never get a correct idle then.

What I dont understand is why you had the ac removed?
 

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Your best option is to see what the ecu see's. The 94-95 mustang obd-2 port is not for the ecu so you cant do diagnostics with it. The self test diagnostics port isnt ideal for testing either. Thankfully henry put a j3 port on the backside of the ecu where you can plug in a moates quarterhorse and diagnose it very quickly.

Thats really your only option.
 
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