Engine Popping noise in the intake. Frustrated still.

[esteban31065]

I have a 1990 Ford Mustang 5.0liter LX. Stock motor,,AOD,, Vortech V3 supercharger 5-7psi,, ProM mass air/24lb injectors,,,Explorer Intake/ 65mm TB,UPR Boostmaster Tube,,BBK shorties,,Flowmaster exhaust,,Walbro255,,Kirban adjustable fuel pressure regulator,, Moates Chip for tuning (tuned on dyno)

It always ran very good up until a few weeks ago.. After getting on it let off to stop and it fumbled and wanted to stall out. Brought home and started to diagnose things.
Turned out to be the rubber line on fuel pump split causing fuel issue. Replaced new fuel pump,hanger assembly, and it included a new plastic hose instead of rubber line, and new fuel filter, after that check fuel pressure and leaks. Car has popped in intake a few times prior to fuel pump issues. So cleaned Mass Air,rebuilt my 24lb injectors, changed out my sleeves on Vortech discharge pipe,cleaned EGR,cleaned IAC,Cleaned TB,,Replaced ACT sensor,,Replaced PCV and grommet,,replaced BAP sensor,,Replaced Dizzy with new Cap,Wires,Plugs (NGK UR5 gap 35thousanths),,Replaced Coil,, Checked for vacuum leaks everywhere!! Timed at 14degrees,, Has no codes(checked many times)
Car has that popping noise when brake is applied in drive between 1500-2000 RPM,, Runs great when mashing the throttle,,When in park has great throttle response. So basically, I am frustrated at this point,My low drivability sucks.Any help is greatly appreciated, ty Steve

 

[Noobz347]

I saw Vortech V3 and 24 lb injectors but I didn't see anything about an FMU.

Have you looked that over?

 

[AeroCoupe]

You are getting no codes at all? I’d say it’s the ECU as I’m pretty sure you should get a Code 15 for the Moates. Typically when you don’t get any codes or cannot read codes the ECU has issues.

 

[esteban31065]

I saw Vortech V3 and 24 lb injectors but I didn't see anything about an FMU.

Have you looked that over?

I never used it,i went to the Kirban Adjustable Fuel regulator when i installed the blower,

 

[esteban31065]

You are getting no codes at all? I’d say it’s the ECU as I’m pretty sure you should get a Code 15 for the Moates. Typically when you don’t get any codes or cannot read codes the ECU has issues,

 

[esteban31065]

I had a code the first time i checked codes. ACT sensor changed that ,and no codes after that,I have a OBD1 scaner but people say there garbage so i dont know. Checked a few more times and nothing showed.

 

[Noobz347]

I had a code the first time i checked codes. ACT sensor changed that ,and no codes after that,I have a OBD1 scaner but people say there garbage so i dont know. Checked a few more times and nothing showed.

There's nothing wrong with my OBD1 scanner. I would hazard to guess that those with complaints either don't know how to use them or have never used them.

The lack of cell light does [not] mean there are no codes.

At minimum, you should be getting a code 11.

 

[esteban31065]

Yes thats all the code i get is 11..and it says system ok.

 

[esteban31065]

appreciate the input, i sent ECU out to get diagnosed.

 

[Noobz347]

appreciate the input, i sent ECU out to get diagnosed.

If this fixes your issues, it will be the first time I've been able to document a bad EEC that gives a code 11.


This is not to say that I don't think you are or are not on the right track. It's just been something that I've been watching out for in the last year or so.

These EECs are "coming due" at the 35 to 40 year mark. I think we have discovered their approximate end dates. heh

 

[gkomo]

I was surprised to hear all the things 'wrong' with my ECU yet the car still ran fine (as far as i know). i'm kind of hoping on the next startup it just magically runs better!

 

[5.0LXStanger]

I have a 1990 Ford Mustang 5.0liter LX. Stock motor,,AOD,, Vortech V3 supercharger 5-7psi,, ProM mass air/24lb injectors,,,Explorer Intake/ 65mm TB,UPR Boostmaster Tube,,BBK shorties,,Flowmaster exhaust,,Walbro255,,Kirban adjustable fuel pressure regulator,, Moates Chip for tuning (tuned on dyno)

It always ran very good up until a few weeks ago.. After getting on it let off to stop and it fumbled and wanted to stall out. Brought home and started to diagnose things.
Turned out to be the rubber line on fuel pump split causing fuel issue. Replaced new fuel pump,hanger assembly, and it included a new plastic hose instead of rubber line, and new fuel filter, after that check fuel pressure and leaks. Car has popped in intake a few times prior to fuel pump issues. So cleaned Mass Air,rebuilt my 24lb injectors, changed out my sleeves on Vortech discharge pipe,cleaned EGR,cleaned IAC,Cleaned TB,,Replaced ACT sensor,,Replaced PCV and grommet,,replaced BAP sensor,,Replaced Dizzy with new Cap,Wires,Plugs (NGK UR5 gap 35thousanths),,Replaced Coil,, Checked for vacuum leaks everywhere!! Timed at 14degrees,, Has no codes(checked many times)
Car has that popping noise when brake is applied in drive between 1500-2000 RPM,, Runs great when mashing the throttle,,When in park has great throttle response. So basically, I am frustrated at this point,My low drivability sucks.Any help is greatly appreciated, ty Steve

Hey there esteban31065, I have almost the exact same set-up on my 90 LX and I'm having very similar issues. Runs like crap at idle, especially until it warms up. Under load when accelerating it can lean-pop through the intake. Under wide-open / hard acceleration it seems to run strong. I have replaced all my sensors, rebuilt my 24lb injectors, and smoke-tested for leaks and still the problem persists. I was able to get the OBD1 reader to deliver the 11 (No Code). I took it to a shop, and they couldn't figure it out, but believe that I am having a fuel delivery problem. The car passes CA smog test at 2,500 rpms, but fails the idle test with high HCs (unburnt fuel) and elevated CO (likely also related to unburnt fuel.) at idle. I have seen many posts with these similar conditions, but I have to date never seen anyone find the definitive problem and post the solution! Here are my next steps: Replace Coil, Replace O2 Sensors, Clean and verify all grounds, test EECIV.

 

[gkomo]

When you say you've replaced all your sensors, which ones specifically did you replace?

 

[5.0LXStanger]

When you say you've replaced all your sensors, which ones specifically did you replace?

Hey there - Thank you for your response and interest - Appreciate you!

Here is a list of all the things I have done on my '90 LX to try to solve this problem:

Completed Tests & Replaced Parts:

• Tested & Cleaned MAF
• Replaced ECT
• Replaced IAT
• OBD1 Tests – No codes!
  • KOEO
  • EEC Advance Test
  • KOER Test
  • Cyl Balance Test
• Cleaned Salt & Pepper connections
• Set base idle w/TPS
• Set base timing – 10 Degrees BTDC w/Spout removed
• Tested TFI module
• Install coolant line to overflow
• Installed new Spark Plugs
• Clean IAC
• Clean throttle body
• Re-torque lower intake
• Tested & rebuilt fuel injectors
  • One was leaking – Replaced w/New
• Run compression check on Stang – Good!
• Test Injector wires with Noid Light - Pass
• Retorqued Upper intake
• Smoke tested both Intake and Engine for leaks

Next Steps:

• Validate and clean all grounds
• Validate all vacuum line routings
  • Smog-pump & Actuators
  • EGR
• Replace Coil
• Replace O2 sensors

 

[5.0LXStanger]

Sorry just realized that I am somewhat high jacking esteban31065's thread... I will create a new post about my problems, and move my post there...

 

[gkomo]

You sound pretty knowledgeable with electronics testing. Is there a way to test your O2's before replacing them? If it runs good at WOT but not otherwise, i know the ECU disregards some things at WOT, so still could be a sensor of some kind.