Timing or not...That is the question

Timing or not...That is the question

Postby herbal_gardens [OP] » February 23rd 2009, 2:00pm

Hi all, I have one for ya. the 97 I bought was running great, until a week ago....Thats when the diseasse kicked into play.

While driving, I noticed that the engine started to feel a bit sluggish, drove it back home and sat in it while it idled, Reved it alittle but it almost died when recieving fuel, then the motor stumbled for a second or two, then went into hi rev for almost 30 seconds then dropped the R's back to normal, almost as if the engine reset its timing.

I drove it for the remainder of the day with no problems at all, then the next morning I went to start it and it was hit and miss with firing, being stubborn as all forum rules starting. So I began rolling it over and shutting it off repetively and on the third time it started, went into hi rev then normalized again.

I have just replaced the fuel pump not so long ago, and under second inspection the psi is normal, the SES light is on but I have had it checked on more than one occasion, and every time it said that my CAT was nearing the end of its lifespan, Im not sure if the engine is getting too much back pressure to operate properly, but given the behavior of the motor it feels like a timing issue to me.....I am aware that the ECM handles all the timing adjustments by its self, so this leaves me scratching my head going WTF. Hopefully someone here has had a similar experiance and can help me out. I love this old van too much to get rid of it, although there have been times that I have just wanted to call it quits.

Thanks for looking and I hope that someone can help.~Chris
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Re: Timing or not...That is the question

Postby Wild Willy » February 23rd 2009, 6:57pm

Probably should get it scanned to see what codes are being set by the SES light- rather than just throwing parts and money at it- I think Autozone will read the codes for free, under the idea that you will be buying the needed parts from them- Could be many things- temp sensor, MAP snesor- as well as the catalytic converter or even an O2 sensor- It the computer is getting the wrong data about what is happening in the engine, it could running too rich or too lean-

Since you said the fuel pressure was good, I am going to assume that you changed the fuel filter in the recent past-
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Re: Timing or not...That is the question

Postby Big_kid » February 24th 2009, 1:20am

Helluva first post, Wild Willy!

He summed it up pretty well!
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Re: Timing or not...That is the question

Postby astro355 » February 24th 2009, 6:29am

You will have to forgive me for this possibly silly question. Does the 97s have MAFs or MAPs?
Diagnose 1st, never be a parts changer!

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Re: Timing or not...That is the question

Postby zombie{[six]} » February 24th 2009, 6:40am

similar problem (kinda) that I had a while ago. Ended up being a bad (or lack thereof) Timing controller (Has a fancier name but cant remember it right now)

Im not sure if the Vortec setups have them or not... chime in anyone?
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Re: Timing or not...That is the question

Postby Matrixx » February 24th 2009, 4:23pm

What controls the the rpms is the ECM. The ECM requires a certain amount of power from the battery to function properly at all times. If their is a problem with the battery or alternator internally (Shorts) or externally (Connections) or receives a spiked power supply directly from the alternator instead of the battery, then this will cause the ECM to spike the rpms.

Their are other factors that can cause this, but this is the most common one and the area I would eliminate first. You do have a MAP and MAF. I don't feel this is a timing issue but more of a power supply or short issue to the ECM somewhere. Hope this helps. Please keep us updated thanks.:)

PS: Just something else to ask and get out of the way here. Do you have "any" after market items Installed in your vehicle that taps into the power supply to the ECM? IE:(Alarms, Remote Start etc.) Thanks.:)
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Re: Timing or not...That is the question

Postby Gus_Mahn » February 25th 2009, 2:18am

Get the codes read, and post them here. My brother had timing issues with his '99 at about 80,000 miles. It turns out some 4.3's have issues with the distributer gear wearing out. My '97's been fine even with 160,000 miles. I think he had some type of distributer or cam sync codes. It took him a while to figure out, and a new distributer cured his issues (occasional missing, stumbling, CE light).
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Re: Timing or not...That is the question

Postby zombie{[six]} » February 25th 2009, 3:58am

ESC module (Electronic Spark Control)
Could be that piece. I had a bad one and had similar issues
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Re: Timing or not...That is the question

Postby herbal_gardens [OP] » March 7th 2009, 6:23pm

Alright, I uncovered the issue. I bought new plugs for the van yesterday and installed them (figured it was a good idea being the old ones had been worked hard when the old fuel pump was still in...The right bank plugs had signs that the engine had been running lean (ie bad fuel pump) so after replacing them I moved to the left bank, and there lay the problem........Plugs 2 & 4 were so loose that all I had to do was put the socket and extention on and remove them by hand... Plug 6 was bridging the gap in the spark plug, the left bank also showed signs of running a lean mix. (has anyone elts had problems with plugs coming loose before, I changed them last year and torqued them to proper level....and all was good (until the fuel pump issue) anyways I just wanted to say thanks for all the input, and also wanted to see if anyone elts has had the loose plug issue.

Thanks again,
Christopher
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