This is the best place I know to get info! I know its not 3rd gen, but sometimes change is good right?

Little history....

I have an 86 Olds Ciera with the 2.5 144K For a while (months) it would ping under slight load. Then, the cold start ups starting getting irregular. The engine did not seem to have the same sound in the morning. It sounded almost labored. When it fired up, I would have to give it a little gas to get the RPMs up. It was like there was no choke on. I know its TBI, but the idle usually raised like a choke when cold. Now it wasn't. Also, there seemed to be a loss of power when accelerating.

Yesterday I spent about $150 just to cover all my bases. New O2 sensor, wires, plugs, cap & rotor, Intake Air Sensor, Coolant Temp Sensor, MAP Sensor, Idle Air Control Unit, new radiator cap, air filter, and new PCV valve. I noticed that the plugs were white which meant a lean condition, which would explaine my pinging correct? Two of the plug wires were halfway off of the rotor! I thought this was my problem for sure.

I buttoned everything back up and took it for a spin. (I hadn't bought the MAP or IAC yet). Still, hard start and wont idle. I drove to Autozone and got the above items and installed them. It seemed to be a little better, but it had a slight...almost miss when I would take off from a dead stop. All other driving conditions were improved.

I know, this is long! This morning I get in to start it up and STILL, hard start (not as hard) and the idle didn't raise smoothly. Still has slight miss when accelerating from a dead stop.

I didn't change the cap and rotor because I ran out of light and its a beyatch to get to. Could this be my problem or should I check somewhere else? Thanks!

 

Yeah, change the cap & rotor, especially if it's never been done. Also, check your timing! You'll need a timing light for that, of course. Over-advanced timing can cause detonation, and if it's way-over-advanced, plug & piston damage.

If you still get ping, but power improves, and just about everything's been replaced, you could go to spark plugs with a lower heat range than stock. A plug that's "too hot" ignites the air/fuel mix on it's own. However, if the pinging goes away, and you pull the plugs, and they're oily and covered in deposits, then the heat range is too cold. A plug needs to get hot enough to burn off deposits and keep itself clean; using too cold of a plug will foul the plug and eventually cause a misfire.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

Fuel filter?

 

Thanks fo the responce! The cap was changed about 2.5 years ago. Seems like only yesterday!

I'll do the cap tonight and keep my fingers crossed.

The only sensor I didn't touch was the Throttle Position Sensor. Reading the manual it states you need an Ohm meter to check it out before you install it. I'm fresh out of ohm meters! Could this be a problem for me?

 

With 140K miles on it, I would pull the throttle body off and check for coking on all the passages. I have done work on several high milage throttle body engines, and they all suffer from the same characteristics - rough idle when cold, crappy off the line pull, hesitation, etc. A little water injection probably wouldn't hurt either...

 

How complicated its it to check? How would I go about cleaning it out? How bad is bad? What should I look for?

Fuel filter was replaced about a year or so ago, but its easy enough to do again.

Any thoughts on the fuel pump itself? I have a pressure guage, maybe I should chech it huh?

 

You'll need to tap into your fuel pressure hoses to get a fuel pressure reading... they're not as "easy" as a port injection system. With port injection, there's a schraeder valve on the fuel rail that takes a fuel pressure gauge. With TBI, you'll have to un-do your supply hose, and connect the gauge between the supply hose & throttle body. The port-injection gauge goes for $40. The "TBI -and- port-injection" gauge goes for $60, and has the adapter hose.

I was told a neat trick from someone on the TBI board. He snagged a fuel feed hose from a junkyard TBI car. He then used brass fittings to make an adapter to take the Schraeder valve of a PFI pressure gauge. He removed his car's fuel feed line from the TB, and put it into his adapter. Then he ran the junkyard fuel line from his adapter to the TB. Or, you could just buy the TBI/port gauge! (Unless you already have it, in that case, I'm glad I'm a fast typist!)

TPS -would- affect the car... and yeah you need a digital ohm-meter. I snagged a $7 "cheap-o" (or is that "special"?) digital multimeter from http://www.harborfreight.com - yeah, it's no Fluke, but it does the job for now.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

Heres the funny part, you would think all these symptoms would throw a code and my life would be easy right? No, no codes. And the light does work.

Years ago (95) it would run REALLY BAD! The mechanic says that he replaced some spark unit by the distributor because it was getting soaked with oil. He said that was the reason for the poor driveability. Boy, was it poor! Anyhoo, he was stumped for the longest. He even put in a new ECM!

I wonder if this could be happening to me again?

 

Good point. The iron dukes seem to have a habbit of leaking valve cover gaskets. I had one in a 85 celebrity. The oil leaked down onto the ignition module and the car just DIED while I was driving down the parkway.

 

How hard is it to change the ignition module? From a couple pictures, it looks like 2 bolts under the cap, on the distributor.

If I take the cap off, maybe I should change that too??

Thanks for all the help. I'll update tomorrow (FWIW)

 

RG,

DEFINITELY check the fuel pressure. I have a long and boring story about fighting a lean condition on a 151 "cast iron monster" and it was a fuel pressure issue.

My problem was somewhat unique, but the result could be the same:



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Later,
Vader
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"Let the bodies hit the floor!"
Adobe Acrobat Reader

 

Oh man, not a fuel pump!! How hard is that I wonder?

Well, I threw some more poop at it tonight after work, cap & rotor, ignition module, and a new rubber valve cover gasket for good measure. Guess what? Yup, problems are still there.

This thing will not start up and run smooth to save its life! I thought for sure looking at the cap that I had fixed it. Here are my problems:

Hard to satrt and stay running at any temp. Once it gets going its all there. Taking off from a stop, there is a slight hesitation and some sort of howling coming from under the hood that increases with the throttle.

Get this, this is the next best part. The car would not start after I came out from Autozone earlier when I bought todays parts. I'm like damn, now what! Pop the hood, take the air cleaner lid of and crank again. Got spark, have fuel? Well, it started eventually. But get this, there was so much blow by coming out of the air cleaner housing from the vent up top. It was some seriouse smoke. No wonder the air filter I bought a week ago is shot! There is a layer of oil from just one day! I cleaned it out last night when I did all the other repairs.

I'm lost! Starts and idles like poop. Runs good when it gets going but with a weird howling noise, and has a ton of blow by! Time to sell it?