Causes Of Pre-Detonation/Pinging

[rude_life]

OK guys my car is pinging pretty bad lately under load but here is a weird one and im wondering if anyone has ever heard of this.."Pinging on Startup". When i crank it and as soon as it turns over, I mean literally withing the fist two seconds the engine is running, it pings. Its so weird because I have never heard pinging while sitting still. This all happens without any throttle. Just at idle right after starting the car. Since I bought the car it has had driveability issues and here is a list of everything I have done to improve the issues, all within the last Month and a half. >>> Replaced Fuel Filter, Replaced Fuel Pump, Replaced Fuel Pressure Regulator, Replaced PCV Valve and Mesh Screen, Replaced Air Charge Temp Sensor, Replaced Coolant Temp Sensor, Replaced both 02 Sensors, Replaced and gapped Spark Plugs, Replaced Spark Plug Wires, Replaced Cap, Replaced Rotor, Replaced Coil, Adjusted Timing at 10*(with spout out), Cleaned MAF Sensor (yesterday), Cleaned and oiled K&N Filter, Cleaned Fuel System with STP Fuel Treatment, and I have never used any other fuel than 91 Octane. In addition to the problems stated above, my car just generally runs like **** and is very slow through the RPM's, It feels like it just cant hold its own weight and like its struggling to push itself along down the road. Very "studdery" very poor driveability. I just got a digital multimeter so I can test my voltage in the TPS, but from what people are saying on the forums, I wont see a big difference in adjusting that, even if the voltage is out of whack. So I dont belive this is going to be a "smoking gun", so to speak. At this point I am frustrated and wondering what the hell to do next, and this is where you guys come in I am looking for any advice that can be passed along.

Thanks...

Kris

 

[Swarzkopf]

It sounds like you need a NEW MAF.

My car was the same way last year. A new MAF made a world of difference.

Do you have any friends with similar cars? Hook up a different MAF and see if the detonation goes away.

 

[WHITE94COBRA]

Check your distributor as well, deffinately sounds like a timing issue. What is your fuel pressure at? Bad MAS could be the culprit as well, check both the dizzy you can pull the cap off grab the shaft move it around? there should be a slight amount of play, or to be really sure pull it completely out of the block, spin it check play etc, when mine went south if I spun it, it had a really bad grinding sound and just didnt spin freely.

 

[BlownFiveLiter]

I'm with Swarzkopf on the MAF being bad. Unplug it, and go for a drive, if that solves the driveablility and pinging issue, you got your answer. Sounds exactly like my '95 a few years back, and I went over everything (timing, fuel pressure, etc), before pulling the plug, and the issue was gone. Ordered a new MAF, and it's been problem free ever since.

 

[94-302-vert]

unplug it?

Have you tried pulling the codes?

Where ya live, maybe someone is close enough to swap MAF with you tor try out???

 

[final5-0]

The outside ring on your hb may have started to spin which would make your timing not be accurate.

Check to see if you got any of that rubber material poking out in the front or back of the hb.

Later
Grady

 

[95BLKGT5.0]

I have the same problem except mine does not do it at idle and I have replaced all the same parts you did.
I have read all and I do mean all of the threads about pinging.
Even the one about the 79 cent fuel hose that fixed that guys pinging problem.
And yes I swapped MAFs with another 95 GT that ran great and mine still pinged.

So here is my fix for the pinging problem.

I am going to replace the hole damm thing. The engine.
Pinging sucks.

 

[rude_life]

Umm what an HB?

 

[tim95gt]

harmonic balancer / dampner

 

[rude_life]

Wouldnt that make my whole car shake?

 

[final5-0]

Wouldnt that make my whole car shake?

Maybe............Maybe Not

It would not have to slip much to make your timing be way off cause you would not know it has slipped and when you line up the mark on the hb to set your timing, it is no longer accurate.

Later
Grady

 

[rude_life]

Grady,
You're the man.

 

[final5-0]

Grady,
You're the man.

I'm just saying that MIGHT be a prob.

IMHO, it does make since cause you say it pings and the power is down.

Before you run down and buy another hb.................

If you want to go to the trouble of finding tdc on your #1 hole, the zero mark on the hb should line up. If not, the hb has started to go bad.

Again, if you see the rubber stuff poking all out around the front or back of the hb thats a good sign of a bad one.

Later
Grady

 

[mo_dingo]

How many inches of vacuum do you see at idle? how many PSI of fuel pressure do you have with and w/o vacuum?
Scott

 

[HoofnIt]

94/95 Computers SUCK!!!! OK, the computers themselves are better but the programming from FORD stinks. There is no way of looking around this fact. I have been preaching in this forum for over two 2 years about this problem. Ford, in their infinite wisdom, programmed the CPU to not only run hot, but to run lean in order to keep the emissions in check. The byproducts of this- lean conditions which undoubtedly lead to detonation, especially in warm summer weather. You NEVER hear about the epidemic problems with detonation in the Fox bodied stangs! Get a custom tune, Tweecer, PMS or PIH and be done with it! PS-I am still having a detonation issue after my HCI and SCT custom tune! I'm so tired of this problem that I am installing a PIH next week! Woo Hoo!

 

[rude_life]

Well I said to hell with it and instead of cleaning the MAF again and again, I went and bought one tonight. OK so i put it in and i would say there is a huge improvement, but also some slight pinging still. I am at 11* timing and im not sure exactly what my fuel pressure sits at since I dont have the gauge, just the adjustable regulator. Something is telling me if I back the timing off a degree and get that fuel pressure set perfect, my pinging issues will be resolved. We will see tomorrow. For the most part, the new MAF has solved the "lagging/ Studdering" problems i have been having.

Thank's guys!!

 

[Swarzkopf]

Did you reset the computer after installing the new MAF? This may resolve the remaining issues.

Glad to hear the MAF helped.