3800 Part Throttle KR *long*

[SaturdaysGS]

As the topic states I'm seeing many degrees (around 7-9*) of part throttle KR, while in BOOST. I can run in 1st gear modulating the throttle just right with PS on to make it run up to about 4k without any boost, but if I press down a wee bit more I can boost, and then I see the kr. :angry: I do NOT have any weird engine noises, no rattling, ticking, knocking, anything. No SES light either.

First things first: What I will do is the "ClubGP remedy" which consists of disconnecting the knock sensors, cleaning off the connections, and then reconnecting them. This seemed to help one of the members with his 97's p/t kr. Only problem is, I dont know where the knock sensors are.

Another thing is I was seeing around 7-9* of KR at WOT in second gear. I held it for only a few seconds (but long enough to know it wasnt JUST burst knock or torque management from the downshift) I'm no dumby! I had injector pulsewidths at 19ms at around 5800rpm or so.

Also my LTFT's are out by negative 8-14% at cruise, in idle, and while under all kinds of acceleration. I'm sure this is going to start taking its toll on my highflow cat, so I'd either like to get this figured out, or get gutted cat, WHILE getting this figured out. :lolsign: O2 sensor isn't too old, have not run leaded gas ever, and I need to replace the FP resistor.

Mods:
3.4 pulley
Ported/Coated PEMS
3" Downpipe w/highflow cat
DHP 1.0
NGK TR6's
FWI
180* thermo
NO MAF screen (eek?)
GTP catback with one muffler cutoff/closed off and a crappy cheapie muffler in place of the other until I can find a good deal or someone to make a 2.5" single catback.
(The story on that ^ is one of the hangers broke and a curb didnt play nicely with the low muffler when I was backing up)

Things to note:
On the OEM battery still, starts fine, VERY easily! Practically like new.
Coolant was flushed not too long ago, runs at proper temp w/180* thermo
Needs fuel pump resistor replaced (hey I have it!)
Has FP rewire and alternator rewire

Help! I dont have full coverage insurance anymore so blowing it up wont fix the problem. Maybe some mechanical / PCM genius, money from my pocket, and such can make this thing more pleasing, I dont want to blow it up!

Thanks
-Nick

Click to read more...

 

[imported_Ron Vogel]

Can you post up a link to a scan?

 

[SaturdaysGS]

Originally posted by Ron Vogel@Oct 24 2006, 02:22 AM
Can you post up a link to a scan?

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I'd love to, but I dont have a logger. I just used a computer program from a laptop I bought from J.E.T to view this stuff real time. Care to scan it? lol

 

[SaturdaysGS]

So I went WOT once today, in first and the car seemed to fall flat on its face in the upper RPM's. Great. It acted like belt slip or maybe spark being blown out, maybe I should change the plugs, they aren't that old though. Maybe 5k miles, at .054 gap IIRC.

Also I have no resonator, and have seen (according to the digital boost gauge which is somewhat accurate) up to 13.#lbs of boost.

Clogged/clogging cat? or maybe just the catback sucks that much since I had to tweak it for now.

 

[Sinister Drag Designs]

a clogged cat would do this,what did you do to your cat back
i still have those mufflers and "Y" you sid you wanted....cheap

 

[SaturdaysGS]

Could it also be bad gas? I filled up at a station in Wisconsin that I've never used before. It was a Marathon IIRC. Used 93, of course.

 

[SaturdaysGS]

I cant edit that post, BUT I was getting better mileage. I compared the trip up which I stayed at about 75, to the trip back down where I stayed at about 85 with that gas on the expressway.

 

[imported_Ron Vogel]

Fuel pump could be taking a dump, car has a few years on it.

 

[SaturdaysGS]

That I could believe, its been running on "HIGH" for a few months now, as well as having 141k on it. Come to think of it it was always very quiet (for a GM fuel pump) until I had to bypass the resistor, then it was quite the hummer, but now, it doesnt seem to be as loud, IIRC. My family also has a tendency to run the tank low and only throw in a couple bucks, so I'm sure that really doesnt help it.

Any way to test it other then just replacing it? Probably should just replace it for peace of mind, especially since I drive to WI every other weekend. Whats the best route per buck? Ed Morad?

 

[M@]

Also my LTFT's are out by negative 8-14% at cruise, in idle, and while under all kinds of acceleration. I'm sure this is going to start taking its toll on my highflow cat, so I'd either like to get this figured out, or get gutted cat, WHILE getting this figured out. lol.gif O2 sensor isn't too old, have not run leaded

there's your problem....

fuel trims that far negative will leave you VERY lean at WOT and cause this knock situation.
The bogging you felt was from all the knock and timing retard killing your power.

You need a real scanner and datalogger dude, you're lucky the thing hasn't blown up yet.

MT

 

[SaturdaysGS]

Thats what I was figuring with the bogging . Where should I start with this car? Ron can you scan it and figure out whats going on/fix it? I'll pay I just need this thing to not blow up before I can put down on a PT over winter.

 

[SaturdaysGS]

Just to touch on what you said Mat, I went WOT with the laptop program I have and the O2's went to about 880 ish and stayed about there so that was that, and I quit. No more beating on it until I get this taken care of.

 

[imported_Ron Vogel]

Originally posted by SaturdaysGS@Oct 30 2006, 05:12 PM
Just to touch on what you said Mat, I went WOT with the laptop program I have and the O2's went to about 880 ish and stayed about there so that was that, and I quit. No more beating on it until I get this taken care of.

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That's pretty lean for a non-ic'd car! Even many IC'd cars can't run that. Generally, .920 to .940 for non-IC, .880- .920 IC'd...but you need to take that with a grain of salt with the narrowband sensor. There are many cars that won't run well under .950's; even IC'd. Depends a lot on engine load and weight of the car.

 

[SaturdaysGS]

Originally posted by Ron Vogel+Oct 30 2006, 09:00 PM-->

<!--QuoteBegin-SaturdaysGS

@Oct 30 2006, 05:12 PM
Just to touch on what you said Mat, I went WOT with the laptop program I have and the O2's went to about 880 ish and stayed about there so that was that, and I quit. No more beating on it until I get this taken care of.

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That's pretty lean for a non-ic'd car! Even many IC'd cars can't run that. Generally, .920 to .940 for non-IC, .880- .920 IC'd...but you need to take that with a grain of salt with the narrowband sensor. There are many cars that won't run well under .950's; even IC'd. Depends a lot on engine load and weight of the car.

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Ron, I know your very busy, but do you care/can you look at it sometime this week? or sometime soon? Since its (the pcm) pulling fuel according to the ltfts, what could that mean?

 

[imported_Ron Vogel]

Could mean a lot of things, bad sensor, bab FP, bad IFR table...the list goes on. Do you have a screen in your TB?

 

[SaturdaysGS]

Originally posted by Ron Vogel@Oct 31 2006, 01:30 AM
Could mean a lot of things, bad sensor, bab FP, bad IFR table...the list goes on. Do you have a screen in your TB?

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Negative. I can't remember how long I have been running without one (a year maybe?) but the car was definately not running this bad when that was first removed. Seems to be that this has happened just recently.

Also since the car is PULLING fueling, I'm thinking that might mean that some sensor is fubared? I would think that if the FP is on it way out and not sending enough fuel.. per say, the pcm would try to compensate by adding fueling. But idk with this stuff.

Is there any way I can rule out the MAF.. minus sending a scan?

Also when I was cruising on the expressway with the laptop running reading the pcm real time, When I would boost in OD, the kr* would jump up and kinda level off, then slowly drop back down close to or even 0 as long as I was only around a couple pounds of boost.

 

[imported_Ron Vogel]

The best way is to swap stuff out and see what fixes it, but that can get expensive if you don't normally have a stockpile of L67 parts laying around. Try the 02 and the MAF first. I know thay you have a newer 02 sensor, but when they go bad, they read slower and generally more rich than when new.