Okay so my friend came over to check out the van. It is definitely pinging. We adjusted the timing some, and had some results, but the pinging is still there. I also filled the tank up with 93 octane to maybe see if that would help. The ping is still present, but seems much less. The other thing is the idle is way too high at around 1500 rpm's. When you ground out the test wire for setting the timing the idle sets right around 8-900 like it should, but goes back up with the jumper removed. I thought maybe it was a ground issue so I ran a ground jumper from the block to the frame, and after that the idle seemed to be right again. Took it for a spin, and the pinging seemed to be gone, but reappeared again during the trip. Also the idle jumped back up, so maybe the ground didn't do a damn thing. Any help? Computer,Distributor? Shotgun?
Chris
Wow...
Start from step one and check to see if the timing belt & marks are correct.
Also you might want to check for a vacuum leak...
Just a thought...
Checked the vacuum leak thing earlier. I can't imagine I got the timing belt wrong as I checked it several times,and the engine runs great aside from the ping.
I had a similar problem with my corolla a few years back where it started pinging so I stepped up from 87 to 89 octane. That worked for a bit till it started up again so I switched to 91 octane. It quit for a bit then started again. So I just drove it like that for about a year till I replaced the O2 sensors. problem solved and it ran great on 87 from then on. As it turns out when an o2 sensor goes bad on these cars the computer sends the fuel map into a closed loop just to keep the engine running(badly). Im thinking all that starting issues you had early on in the thread may have burned out a sensor or something. could even be a crank or cam position sensor come to think of it.
Crank position sensor is built into the distributor, so not a cheap fix I suppose. The o2 sensor is easy enough to get to, so maybe I should just try replacing it anyway. Come to think about it the idle was high before the head replacement, but I attributed that to the fact that the engine was running so cold with no thermostat that the ecu was running it higher to heat things up.
I am frustrated because part of the reason I got this van was the fuel injection that all my other older fun cars lack. I thought it would make life easier on me than the old carbs. I was wrong!!
Thanks guys,
Chris
Pinging when not under load ? Wierd.
Is it possible that the distributor, I refuse to call it a dizzy, could be advancing the timing when it shouldn't. ?
So I bought a new o2 sensor today, and when I went to install it I found the connector on the wiring harness was missing the plastic body of it, and was only the bare female connector. It didn't appear to be plugged into the o2 sensor either. I plugged it in, and took it for a spin. Pining seems to have disappeared. Must have been that, huh? Why didn't it throw a check engine light with the 02 sensor not being hooked up? How important is it to low load running of the engine? I ask because it was pinging mostly under very light throttle input/loading.
Do you think I should install the new o2 sensor anyway? Oh yeah I installed a new cap and rotor as well. I had bought a new pair from RA, but they were wrong, so now I got the right ones from AutoZone.
Chris
well.. as most electronic parts are not returnable.. might as well put the new o2 sensor in
I'd stick it in just for S&G, since you already have it.
Well I drove the van around a fair amount today. I thought the pinging was fixed as I drove it earlier in the day without any occurrences, but just now on my trip home from playing hockey it started to do it again. Maybe I didn't fix it. I think I will put the o2 sensor in tomorrow just for S&G's.
Chris
Look also at the EGR system. Improperly working EGR setups can cause pinging.
Does it make any sense that the engine only pings under light throttle, but not under heavy acceleration? It looks like the timing belt is lined up correctly, and I have the timing set to factory 5* BTDC with the test wire grounded out. How much damage am I doing with the pinging? I looked at the plugs on Saturday, and they look fine. It runs so good aside from this ping,and it seems to get worse the longer I drive the van.
Chris
I bought some new tires from the tire rack last week, and had a local garage mount them up on my Starion wheels. Wouldn't you know I go to pick them up and they had them all mounted with the wrong side mounted out on every one. How can you do that when the tires have "this side out", and "this side in" printed right on them?
Amazing!!!
Trade it in on another Mazda, not helpful but they don't give you these issues do they. 
Nope my Mazda's have been rock solid!!!!!
Just spent the day rechecking the timing belt by removing it,and re-installing it. I know I have it dead on, and had the timing set to the factory 5 BTDC. It still does the same thing. I reset the timing to around 2.5 BTDC, and it still pings. Any other ideas? It is only happening under light cruising throttle, and not under heavy acceleration.
Chris
06HHR
New Reader
6/14/12 2:30 p.m.
In reply to Mazdax605:
Shooting in the dark, but here goes.. Are you using stock spec plugs? If not, do you know if the plugs you have are the right heat range, they could be too "hot". Could be carbon deposits in the combustion chamber, maybe try running some seafoam through a vacuum line connected to the intake.
I used brand new NGK BPR6EGP plugs in the new head. They are platinum,and recommended by the owners manual. The piston tops all looked great when I was in the engine. Newly rebuilt head that looked brand new if you ask me.
I’m not sure what the crank damper looks like on the van but is it possible the outer ring could have slipped making your timing marks off? I’ve seen this happen on a few small block Chevy’s. How far can you back off timing before it wants to stall?
Another though, does the distributor have a vacuum advance? If so is it hooked up to port or manifold vacuum? What if you disconnect it and go for a drive? Does the pinging stop?
What grade of fuel are you running? This is also a long shot, but my first car was a Plymouth Reliant and it would ping like mad under load running regular but if you put premium in it wouldn't ping at all. So we just ran premium in it and it got driven ~100,000 miles like that.
06HHR
New Reader
6/14/12 3:13 p.m.
In reply to Mazdax605:
Sounds like you've pretty much eliminated every possible cause except the distributor and the ECU. Could be a faulty sensor that's telling the ECU to advance timing when it shouldnt. That issue with the idle could mean a faulty ground at the ECU. It is strange that you only get the pinging at light throttle and not under load, it's usually the other way around. You may have a worn-out distributor. I dunno..
No vacuum advance on the distributor. The ECU takes care of that. Running 93 octane the last two tanks. Could it be a gummed up injector or two causing problems?
Got a timing light ?
Could give you an idea what is going on.
I do have a timing light and I set the timing right on the mark at idle.
You know what is odd? Before I put the belts all back on the front of the engine i turned the engine over by hand 4 times to make sure the marks on the crank, and cam lined back up again. They did, so I was convinced I have the timing belt correct. That is aligning the mark on the cam gear,and the main crank gear for the timing belt. With the main pulley gear back on the timing mark on it lines up with set of marks on the timing belt cover. With that in place and, the mark on the cam lined up the mark on the main pulley is at the 5* mark. Does that make sense? Now I know that is when I should be getting the spark on number 1 cylinder, but it isn't where the marks should be lined up normally I would think. I know the pulley only goes on one way,and I have it right. It has a hole in the face that aligns with a pin in the gear pulley.
Chris
