1995 2.3 4 banger 5sp manual I've tried everything i can think of , I'm running 87 octane , Have tried octane booster , 89 and 92 grades of gas
Is there anyway to change the timing on this thing? I've had the thing checked wirh a scanner I dunno, it does it real bad when i level off the throttle at about 50 mph and when climbing it pings i have to drop it into 3rd or i won't make it up the hill . anybody have this problem.

 

Try using Sea Foam. Odds are there is a lot of carbon buildup causing the truck to ping, and Sea Foam will help clean things up a little. There is a detailed how to on using Sea Foam in the how to section. Basically, let the truck suck in 1/3 of a can through the brake booster line and then shut it off and let it soak for 5-10 minutes. Then, start the truck up and let it run until it stops smoking. Pour another third of the can in the oil and the rest in the gas tank. Sea Foam is available at any car parts store in the same section where you find the octane boosters.

 

i've tried sea-foam , thanks for reply

 

Hello Bob and welcome to R-F.

Sorry to see you had to post twice on the same problem and don't seem to be getting many good responses.

First, I don't know the 2.3 from a hole in the ground, although my 79 Mustang had one, 28 years ago, lol.

I see you tried cleaning the MAF. I'd suggest driving it with the MAF disconnected. That forces the PCM to use "canned" values as a default. If it runs better disconnected, replace the MAF.

I am going to mention the normal tune-up stuff. Is this the engine with 8 spark plugs? I would at the very least, pull them all, clean and re-gap them (or replace them).

I'd also look at your plug wires. I've found many bad spark plug wires by lightly misting them with water while the engine is running (vary the rpm). If it spits and sputters, you've found the problem. It is very helpful to do the spraying in the dark. You can then SEE the arcing. Don't forget about the coil / coilpack, whichever it has.

I must also mention your air filter. You can rule it out by removing it and driving a short distance to test for the pinging. Can't hurt to clean your air intake/throttle body with some carb/choke cleaner.

You could also have a bad vacuum leak. This sometimes shows up as your vent/heater directing air out of the defroster, regardless of selector setting. It may only do it when accelerating. Just put your fan on high and see if your air gets sent to the defroster. Would likely have idle issues tho'.

A lot of the old-school mechanics use vacuum readings to troubleshoot engine problems. May be worth buying a vacuum gage. (Google: vacuum gage readings, lots of hits there)

You didn't mention any idling issues, so I don't suspect your EGR valve being stuck open.

Clean / replace your PCV valve. Inspect the hose for cracks.

Does it smoke? Is there black soot built up in your tailpipe? Oil consumption?

What is your temp gage reading? Could have your thermostat stuck open and the engine never gets warm enough to run properly (yes, even in AZ). That also brings up the IAT (Intake air temp) sensor and ECT (engine coolent temp) sensor. Either of these could fool the PCM into programming timing or fuel wrongly.

Lastly, you can do a compression check. I didn't see your mileage, but if it's high, you could have bad rings or a valve problem. The compression check should be done twice, first dry, then wet.

You might also post this question in the 4 Banger section, or ask the Moderators to move it over there for better visibility. Good luck with it. If nothing else, I've given you a few things to rule out before the experts chime in.

 

Thanks earl for your reply, I have done everything you have suggested, I've been working on this for a long time , talked to techs , none of them have an answer for me. I have put new plugs, wires and changed every sensor on this thing, new cat and 02 sensors, EGR , IAT, i have 233,000 miles on this thing , doesn't smoke , knock or
consume oil or leak it , truck is in good condition except for this prob. When i disconnected the Maf it would barely run then die. the idle doesn't come down when your driving it for at least 10 seconds So i suspected the IAC put a new one on it , that was worse ,I've removed the manifold cleaned everything still no change. no vac leaks haven't changed the ECT , Engine runs normal temp even when it's 115 degrees out here, But i have noticed that it doesn't start doing this till it warms up to normal. it does the idle prob from start up.It has 8 spark plugs, compression is good.Do you think it could be the PCM Also it didn't do this when i first got the truck.

 

trade it for a dog and shoot the dog that will fix all the problems

 

It figures a chevy man would say that lol , but your no help

 

if its pinging, could it possibly be valves, springs, rocker arms or any of that stuff
I know on my van it pings, and under acceleration it gets worse, valves are bad or need adjusted or something
maybe your truck is the same way?
just a suggestion anyways

 

hi M50B06 , I am probably headed in that direction next givin i have a lot of miles on it , thanks

 

anytime
i always try to help whenever i can, or at least ill put out silly options that may or may not help

 

I'm reviewing the 97 2.3 manual for Pinging: ECT, PCV, compression, fuel pressure (35-40 psi), fuel injector o-ring leak, spark quality, plugs, wires, Crank pos. sensor, Cam pos. sensor, Octane adj. shorting bar (removed?), air intake leakage (the hose system from airbox to throttle body).

Some are common to the "slow return to idle": Air intake hose leakage, PCV (rattle ok, hose holds a piece of paper test), dirty throttle body.

Keep in mind, this is from the 97 manual (OBDII vs. your OBDI).

Coolant temp sensor is simple to check with an ohmmeter and some hot water. You should see 37.3k ohms at 68 deg. F, 3.84k ohms at 176 deg. F and it should change smoothly when you immerse it. I'd look at that and its wiring (LG/R and GY/R?).

I know my 3.0 would ping when my EGR DPFE was going bad (twice). It finally tripped the CEL and a classic DPFE code. That's about a $60 part (is yours metal? the metal ones corrode- replace it with plastic). Common failure item, btw, but doesn't cause high idle, that I know of.

That's a lot of miles on your truck, but it should be fixable. I seriously doubt it's the PCM.

I'd throw a PCM coolant temp sensor at it. Shouldn't be a very expensive part, I'm thinking less than $20. It only does it after reaching operating temp (closed loop), so I'm thinking sensor, either EGR DPFE or Coolant temp.

The high idle sure sounds like a vacuum leak, but it could be the TPS. You didn't "adjust" the throttle body setscrew, did you? DON'T. That'll mess up the TPS setting.

Did you disconnect the battery to reset the PCM when you replaced the IAC? If you still have the new IAC, I'd install it and let it re-learn the idle. Disconnect the battery for a few minutes, start it, don't touch the gas, let it idle 10 minutes, then idle 10 more with the AC on. Do that for any sensor replacement.

I'd inspect all the vacuum hoses too. That truck is getting old, it's hot in AZ, and vacuum hoses get brittle and crack/break.

Are you able to get ANY codes? You don't need a code reader for that year.

 

Hey Earl, Thanks for posting back again. My truck is OBDII , Manufactured
late in 1995 , connector is under steering columm. so when i plug my scanner in i have to imput the year 96 for it to read. I show no codes after scan scanner shows successful when finished the only code i had recently was for the canister purge valve $80. replaced it cleared the code and rescanned every thing was fine. I think i'm gonna replace the coolant temp sensor and maybe the EGR DPFE., mine is the metal one, I've replaced all the vacumm lines already. I didn't touch the screw on the throttle body but i have replaced the tps a while back thinking that was the problem. I didn't diconnect the battery when i changed the IAC, I'll do it the way you said after i change the other sensors. Because it is so hot out here i check my vacumm hoses often and change my battery every year regardless. I'll let you know how everything works out . Thanks again Bob

 

You stated you have 233,000 miles on the truck.When was the last time the timing belt was changed ?

 

I changed the timing belt at 110,000 and again at 185,000 miles

 

Good point on the timing belt.

Potential exists that it skipped a tooth since replacement or was not perfectly lined up when last replaced (although it would have immediately jumped out at you if that were the case; you'd have certainly recognized a new symptom- pinging - directly after replacement). The PCM can only adjust timing so much.

That tensioner looks pretty robust, but it does say to rotate twice, and verify the marks line up before tightening the tensioner. I suppose it couldn't hurt to verify timing is still correct.

Reminds me of setting the timing on my 64 Fairlane 260 V8. It had a lopey idle, gobs of power and sucked down the gas. 16 y.o. Earl had no timing light. Old boy down at the corner gas station wouldn't look at it for free, but did tell me to put a glass of water on each fender and adjust the distributor until the ripples matched. Close enough!

 

I think it's carbon build and/or egr related.

The conditions and work you describe.. not a problem when cold (excess fuel), sea foamed (cleaned injectors to some degree) moderate loads (low rpms / lugging) and having replaced a lot of parts the typical parts, all tell me the EGR is not opening, it's plugged up, or you have excess carbon built up.

I guess first things first though. Do plugs from all cylinders look the same color? If ones off color from the rest then maybe you have a bad injector.

If they are all the same dump 2 bottle of "techron" injection cleaner in one tank of high octane fuel w/ cleaners in it. (I like shell V power) Then for that tank full of fuel flog it. Go WOT at least a few times in first and 2nd gear each day. That will help get rid of the carbon.


Rich

 

When i changed the timing belt i double checked the marks and made sure they lined up by tuning it twice like the book said even after i tighten the tensioner no mistake there Earl, thanks for suggesting it. this pinging problem started at about 170,000 miles. way after i changed the belt the first time and before the second time. pretty baffling to say the least. Hi wydopnthrtl, thanks for your reply , i kinda agree with you about the EGR may be plugged or something, when i replaced the EGR valve the manifold holes were plugged solid that's when i pulled the intake and opened the holes up , imight of missed something , i dunno or maybe the tube leading to it might be plugged ,I'm gonna check that all out here pretty soon. this stuff really gets me ,I'm from the old school you know points and condenser era lol. plugs all look the same . I did the ijector cleaner thing too. could be the EGR DPFE .

 

The EGR allows inert gasses into the combustion process. That means less fuel and less oxygen are present. The PCM is trying to achieve stoich by reading the 02s... and if the EGR is not working you now have a leaned out imbalance of a/f. That lean burn combined with timing, carbon buildup, and high loads usually shows up in pinging first. Incereased fuel consumption as well.

Rich

 

I recently solved my pinging problem when I found that the cold air intake was leaking between the throttle body and the MAF. The hose clamp had been over-tightened causing the inner piece of tubing at the joint to collapse on itself and leave a very difficult-to-detect triangular opening that was visually obscured by the outer hose at the junction. I used a little heat to make the plastic pliable and bent it back to the correct profile and reconnected the hose iwthout excessive clamp tension. The problem was solved.

 

Im having this issue as well , Im just now starting to look into it .

 

Seems like you have taken pretty good care of this thing but I haven't read here if you have replaced the fuel filter. I've had that cause pinging in other vehicles and it might explain the lost of power too. Just my .02

 

I have a 2004 for the last 6 months and it is pinging. Like i said it is a 2004 with 39k and getting worse. Only really seems to do it is under accelleration. I just wanted to see what other people have found out with the 04 models. I installed a new air filter and started to replace the pcv valve today (What a pain) but ran out of light. Shoot any new info my way. Thanks elgin