Detonation/Pinging

[wacorider]

Hello all you Ranger fans...thanks for the help on the electric window...the repair was very easy, once you know the secrets

Long standing problem...93 Ranger, stock, 4 liter, 4x4, 292.000 miles...been having a problem with the motor detonating, sometimes called pinging, at rpms above 3000 on acceleration...not a fuel problem, all sensors gathering data have been replaced within last 10 months, including rebuilt injectors ...problem seems much worse during the hot months...runs well cold, as in the winter time (I'm in Indianapolis)

Have not touched/replaced the Ignition Control Module (Sometimes called the EI Module in the Ford Dealer Service books) or the Powertrain Control Module.

Each of the last two mentioned items are about $140 each to replace, but I would rather understand the problem, than just throw money at it.

I do not have a diagnostic device, so I cannot check codes.

PS can anyone recommend a diagnostic device , ie what, where to buy, etc?

Thank you!!

Doug B

 

[Earl43P]

You CAN check codes without a reader: http://www.therangerstation.com/tech_library/OBD_I.html

With its behavior being outside air temp related, you should test/replace the IAT/ACT sensor.
http://www.oldfuelinjection.com/?p=29

It has a lot of input into the fuel mixture equation (injector pulse length).

 

[GentleRF]

Doug,

I would find an AutoZone, they have the test equipment to read the codes right there. If my rigs were newer, that is where I'd go. '95 and newer can get the codes read. My '94 Geo Metro and my '86 Ranger are not readable.

I hope this helps,

Rick in East Bremerton

 

[RonD]

Pre-detonation , pinging, under load can mean the EGR system is not working as it should, if you have an EGR system.
The EGR valve opens only under load, the exhaust gases help cool the cylinders so fuel mix won't ignite to early.

A dirty tube or valve will lower the flow of exhaust gas, pinging under load would be the result.

Lean mix will cause pinging, a lean mix burns hotter and cylinder heats up causing the lean mix to pre-ignite as it enters the cylinder.
Carbon build up in the cylinder from past rich running can aid in this pre-detonation, did the engine have a run rich issue in the past?
As said the air temp sensor controls mix along with the MAF.
Colder air is denser so computer runs engine a little richer, hot air is thinner so a leaner mix, but maybe too lean.

The perfect fuel/air mix is too lean to run in an engine, pistons and valves will melt, pinging can be a sign of getting too close to the perfect mixture, so should be avoided