What is Wrong with my Car???

[Hognose]

Ok here is my last Track times;

60ft 1.742
330 5.180
1/8 8.156 @ 82.43
1000' 10.78
1/4 12.985 @ 100.79

I am leaving on 2lbs of boost, with30lbs of air in my drag radials. I am running 25lbs of boost though!! What's up? O2's are in the low 800's. Fuel pressure is at 39 psi! Car pulls very hard in 1st & 2nd just not in third.
Just turned timing up 4 degrees in the 3/4 and saw no real difference on the Direct Scan. Tried adding timing in the 1/2, car didn't like that!
I have replaced all sensors. Tried running open exhaust and so no difference in times. Runs smooth, no smoking except some black smoke from being rich. Injectors are brand new, had same problem with old injectors.

I am at my wits end with why this car is running over a second from what it should in the 1/4. Could a loose timing chain cause this? What else could it be? Thanks

Matthew

 

[Blazer406]

Ok here is my last Track times;

60ft 1.742
330 5.180
1/8 8.156 @ 82.43
1000' 10.78
1/4 12.985 @ 100.79

I am leaving on 2lbs of boost, with30lbs of air in my drag radials. I am running 25lbs of boost though!! What's up? O2's are in the low 800's. Fuel pressure is at 39 psi! Car pulls very hard in 1st & 2nd just not in third.
Just turned timing up 4 degrees in the 3/4 and saw no real difference on the Direct Scan. Tried adding timing in the 1/2, car didn't like that!
I have replaced all sensors. Tried running open exhaust and so no difference in times. Runs smooth, no smoking except some black smoke from being rich. Injectors are brand new, had same problem with old injectors.

I am at my wits end with why this car is running over a second from what it should in the 1/4. Could a loose timing chain cause this? What else could it be? Thanks

Matthew

What kind of shape is the tranny/converter in? Are you locking it? If so, when? It does appear to be laying down....should be easy 12.7's or so.... at like 105 or something.

 

[Hacksaw]

25 lbs of boost? I wonder if you're detonating. What octane fuel are you running?

Is the black smoke at part throttle or WOT? If it's PT, then your O2 sensor is bad. AT WOT, then I would look at the Air/Fuel ratios on your chip since the stock type O2 input is ignored (since it's out of range) at WOT.

Also, is the wastegate solenoid working right?
-Mike H.

 

[evil666]

I think like Hacksaw said you might be detonating at 25lbs of boost and maybe you have to much timing, especially if you are on alky and pumpfuel. Instead of bringing your timing up you should try and bring it down and maybe even your boost for now to play it safe if you might be running lean.

A= What are you using to monitor your 02 and kr? I use a otc 4000e and when the o2 are in the low 800's that is lean, like in your case.

B= What are your KR? Do you hear any pinging?

C= Is your fuelpump ok? Do you see any drop in fuel psi when you floor it on top end?( only if you have an exterior gauge) Make sure you have over 12 volts going to your fuelpump with the engine off and over 13 with the engine running. Is 39 fuel psi with the vacuum on or off?

D= This doesn't have to do with your problem, but what kind of drag radials are you using, because I think 30 psi of air in your tires is probably too much and if you would lower it, you should inprove your 60ft times. I put 16 psi in my MT drag radials and it hooks great for me.

86 Grand National t-top (59900km)
stock long block,stock suspension, red stripe convertor, te44, smc alk injection, 24lbs boost, 94 octane, hooker cat back with dyno max ultra flow muffers, tomco 30lbs injectors, dynotech stage 4 street chip, thdp, mease 24 row IC, Ron Custom max boost brake module, MT drag radials (275/50/15) 3800lbs race weight with driver.
BEST E/T
60FT=1.52
1/8= 7.38
I/4= 11.74
MPH=113
BESTMPH=114

 

[QUIP'6']

i know turboman38 almost the same setup running low 11's with a 2800 convetor that te-60 should be a loww 11 high 10 sec time

 

[corsair231]

What kind of shape is your maf in? Are you seeing 255 gps? If you are not you may not be getting max fuel. Alky should be helping but you may still need more.

 

[Hognose]

Thanks for the replies!

My Trans and converter are new and strong, My 02 Sensor is a new GM unit, I have a walbro 340 Hotwired and am getting 1lb of pressure for one lb of boost @ WOT. I am using a Scanmaster and Direct Scan to monitor my car. I have recently replaced my MAF with a known good GM unit. 30PSI with the vaccum off.
I know I could lower my 60ft by dropping the air in my tires but that is not where my problem lies. I just wanted to show that the car is coming out of the whole very strong even at only 2lbs of boost. Plus I am only gaining 17 to 18 mph in the second 1/8th!
Here is an example, my buddies Z06, we have almost identical 60ft and 330ft times, then from 330 to the 1/8, I have fallen off pace 3/10s! and then over a second in the 1/4!

Thanks, keep them coming!

Matthew

 

[XLR8]

You only gained 18 mph fro the 1/8 to the 1/4. Do you have original valve springs? If so, that could be an issue. Is you converter locking?

 

[Eric Stage I]

Do you have a directscan run to look at?

Regards,
Eric

 

[SHADOWII]

Have you tried taking out some fuel or maybe lower your alchy charge. mine started laying down w/ the cooler outside temps. A couple of times, the volume of alchy (using a mix of meth and denatured) blew out the wick! the car just laid down.

 

[Blazer406]

You have a DS log of that run?

Send it to bdykes@beabulldog.com

I won't promise anything... but I will see if anything is obvious.....

 

[HiTech6]

fuel pressure

30 lbs of fuel pressure with line off? You may want to try to increase this to about 44-45 line off. Hope you find your problem.

 

[Hognose]

I replaced my valve springs with comps just 2 months ago. I am running 39 psi fuel pressure line off. I do have DS readings I can send Just need to get home. Not sure if the convertor is locking. I am not manually doing it.

I would also like to mention that the previous owner of the car (who is a good friend) had gone 8.7 in the 1/8 @ 90mph with only 15lbs of boost!

the car doesn't burn any oil and the plugs look great. I have had this problem for a while now. I have even pulled the fuel out @ WOT and seen no difference. The car seems to gradually loose it's pull. 1st gear is just as it should be, it was cold the other day and it was spinning the 275 DR's at the top of 1st and then again when it hits 2nd. Thanks for the help!

Matthew

 

[Hognose]

Sent some DS file to Eric & Blazer 406.

Anyone else have any ideas? Thanks again.

Matthew

 

[Blazer406]

ds file

After some looking..... here is what I saw.....

Right after you went to WOT... O2's went down and stayed around 24 mV (mega lean) until you go past 12 mph..... you had a few knock counts early in the run... but no retard.....

Timing is pretty conservative @ 22 deg for 1st and 2nd.... and 20 deg in 3rd.
You might benifit from increased timing in 1st and 2nd for sure.

It also appears your converter is pretty tight. It only went to about 2200 RPM when the car started to move...... (was this on sticky tires?)

O2's went above 831 mV @ 13 mph .... and as high as 871 mV .... not ever going down significantly until around 66 mph... when it went down to 810 mV. This appears too rich to me....in that range. I have always been told 790-800 mV is the goal..... I don't know how much that is hurting you.... but it is rich there...


O2's after that look decent... hovering around 800mV until you let off around 90 mph......

All in all... nothing earthshattering.... like I was hoping to find..... but that is what I saw.... Hopefully someone else can chime in who looked at it and find something I didn't see.

HTH

 

[John Larkin]

Don't worry so much about the fuel pressure reading. Watch the 02s. An EGT would be nice to add for monitoring. I had my FP down to 37 line off on my best run. 02s were 740 with 0.8 KR, just a tickle one time. EGTs were about 1500 which is up there but not totally unsafe. Leaner and meaner was great but then I realized I needed to drive it home about 70 miles.