Vader, I know you have AFR heads and a supercharger on your car, that's one of many reasons I am asking for your help. Here's my problem. I just finished a motor swap. My stock 91Z28 has a paxton Sn2000m....I know you hate paxtons and i regret not getting the ATI. Anyway, I put a new motor in and have just over 100miles on it. I was running a code 32 so i pushed on the diaphram, it seemed to be stiff until i pushed on the diaphram, then it seemed to free up some. I now have no code 32. My problem is that my car seems really sluggish? my new l98 has the stock tpi intake with slp runners and ported plentum and base, ford 24lb svo injectors, 190AFR heads with the heat risers, custom cam @.050 208/222 with 475/505lift, crane hi-6s igntion, Fuel psi set at 45psi, tes headers, dual cats, and a flowmaster cat back system. The car seems slower than when the stock engine was in the car (with out the supercharger). Do you have any idea what is going on?? My vacume is at 15.5 inches. I checked for intake leaks with starter fluid...none evident and my vacume gauge is steady at aprox 15.5inches of vacume. Any help would be Greatly appriciated

 

I forgot to add, I do not have the supercharger on the car as of yet. I plan to put it on in a few months once the engine has a few miles on it. Also, when the car shifts, it feels really strong but the rpms build really slow?

 

timming is set at 6deg advanced.

 

Are you still running the stock prom/chip in this car? If so thats your problem. You will NEED some custom tuning done to the chip to get any type of performance that your looking for. If you haven't been to the DIY PROM board I would recommend pulling it up and reading for a few hours..

Brendan

 

man i wish i was Vader i have an idea or two about your problem. oh well i'm sure he'll see this sooner or later.

 

hehe, not this again.. 'vader, glenn, help help!!' i thought everyone was over this about a year ago.. oh well, guess i cant help either..

 

Think I figured it out. I took some starting fluid and brake cleaner and sprayed the termianls where the egr connect to the solenoid next to the coil. Then I advanced the timming to 12deg advanced and it runs great with no codes Now I think It may be time to get the prom burnning materials. Thanks for all of the help!

 

NOPE still have the code H E L P please anyone

 

sorry I'm not Vader so I guess I can't help either...

 

Craiger, do you have any captured scan data? If you don't have a scan tool, do a search on "Craig Moates" as he has FREEWARE (though donations accepted) where you can capture the data.

Yes, your eprom should be optimized and it could be part of the problem. Sometimes (on modified engines) the stock "conditions" for an SES error test will need to be changed. This is because occasionally what GM defined as "out of bounds" is now "in bounds" in typical driving.

This is all assuming that you don't have a "mechanical problem".

 

Glen,

I do not have any prom burning material. What will i need with the craig motes softawe? I am debating on burning the chip my self but i have a friend who is an expert on EFI cars who will burn a perfect chip on a dyno for 350$. Anyway, I had a similar setup in my 87 vett except the cam was a bit larger and i had the 200cc tws heads and i never ran a code with the new mods? I can push the diaphram with my fingers on the egr. HOw much vacume should the egr need to move the diaphram? And what exactly will happen when i apply the vacume to the egr? If i remember right, it will make the car idle like crap? By the way, i forgot to mention that when i first start my car cold, it idles rough but once it warms us is sounds ok...but it still lacks power

 

i just put a vac pump to my egr and i can hold vacume to the egr while the engine is off. When the car is running, i am unable to get any vacume to the egr? Is this normal or is my egr bad? I can move it with my finger but what should the vacum pump read or do??

 

Craiger,

There are a couple of things that come to mind as I read your post. First, I try to discourage anyone from posting for help from a specific person. It tends to discourage other prople from reading your posts and offering help or suggestions. This is a community board, and everyone should be included. If you really want specific help, there are email links for those communications. A few people have already made reference to that thought.

Your post was apparently read by several of the more skilled and qualified tech experts, but they already mentioned that they would like to help but... That's too bad, since you probably would have had some really good advice from any of them.

Leirch is right, and you're really lucky that Glenn gave you some tips. He is certainly one of the aces on tuning. I'd listen very carefully to anything he had to offer. When it comes time to burn that PROM, pray that he replies.

As for me, you may have had some misinformation. I don't have AFR heads. I have factory ported heads on a few engines. I also don't believe that the heads are your problem.

I don't have a charger, either. I'm about as naturally aspirated as a cheap hooker, and really don't have any basis for disliking one brand of blower over another. I'm sure they all have their advantages and disadvantages. I do know that Paxton has been in the centrifugal blower business longer than anyone other than G.E. and Allison. They've been making high speed industrial blowers since the '50s or '60s, and some of those are still running.

As for your EGR, you apparently have been able to move the diaphragm and verified that the valve will open. It holds vacuum with the engine off, which means that the main diaphragm is intact. The reason it will not hold vacuum while the engine is idling is that it is a backpressure type valve. It has a pilot valve that controls the main vacuum diaphragm, and the pilot valve requires exhaust backpressure to hold it closed so that the main valve can operate.



There is a chance that the EGR is O.K., but these are very difficult to diagnose on the car. Unless you have or can rig a fixture that will apply a pressure differential across the valve ports, you'll have a tough time getting it to operate on the engine. If you have an electric vacuum pump, you can simulate backpressure by restricting the exhaust and applying a vacuum pump to the main line. You can also remove the valve, use a handheld vacuum pump to operate the valve and a shop vac to create the differential from the intake port side, and get the valve pintle to move if the valve is good. The valve should operate at that point, but only until it begins to open and pressure across the valve equalizes. You almost have to watch the valve while an assistant restricts the exhaust or applies the shop vac, then watch closely.

Of course, when the valve is installed on the engine this all depends on the EGR vacuum solenoid operating. And it depends on a pressure differential across the exhaust passages in the intake and the intake runners. If you have a positive or near-positive pressure in the intake tract because of a blower, you can probably forget about the EGR valve ever opening. Your best chance at that point may be to retrofit a port style EGR valve (one that operates directly) and hope the ECM controls vacuum under the correct conditions. You could also try a negative backpressure EGR since the intake will have a more positive pressure, but throwing money at EGR valves just to try might not be the best way to budget.

Maybe someone who has been down that road could help, maybe not.

Let us know how it works out. And try to be a little more inclusive in your post titles. Just trying to help.

 

You are aware the EGR doesn't function while idling. This is where having eprom burning equipment could be useful in diagnosing a problem - you could FORCE the EGR to operate in idle to see if it's working properly. I've used my eprom buring equipment a few times like this.

 

Glenn, Thank you !!! I found a coupple of sites that show you how to make your own aLDL interface via a serial port connector and a DB9 with some resistors. I am considering either doing that or spending the cash on the kit. Will i need a Scan tool??

Vader, Thank You for answering my question on the EGR! Let me explain why I called you... I had posted this topic on the tpi board, this board, and the engine swap board and i got no reply. That is why i specifically called you, and because you always have good advise. As far as you not having AFR heads and a blower, I think i had you confused with Willie Sorry. But Thank you for the schematic and your Great information on the egr. I don't think my egr is bad but i do question the solenoid the vacume lines go to? Anyway, I'll keep you posted on my results.

 

Also, do you have a relocated MAT sensor and is your ambient air temp under 40*F? If so, the EGR will not function EVER when the ECM detects an MAT reading less than 40*F. The MAT has an even more pronouced effect on other things on SD cars, but on both SD and MAF cars, relocating the MAT will cause the EGR to cease to function at much higher ambient air temps since the ECM is expecting the MAT to be inside the plenum and heated much higher than the ambient air temp.

On my SD car, I had to lower the "EGR Enable Temp" to get my EGR to operate properly with my relocated MAT and the ambient air temp went under +40*F.

I just thought I should point that out to you.

 

Not sure if i mentioned ti but my car seems to idle really rough when it is cold but then stops running ruough after a coupple of minutes? could this be the egr or the egr solenoid?

 

Given your modifications, I suspect your calibration is off. When you first start, you are in open loop and running off the tables in the eprom. If the modifications you have made have not been reflected (and tuned) in your eprom, then while you are in open loop you will be "off" and possibly rich since SVO 24#s tend to act like 26-27# injectors (depending on your fuel pressure).

Once the engine "warms up", the O2 sensor is functioning and now correcting the mixture. But this probably indicates that in WOT that your mixture is off enough that you are not getting the performance you should (since you run off the tables in WOT).

There are more of us "WestCoast Guys" getting into eprom burning. I've had a number of phone calls and actual people coming to visit me to learn how to do it. It's amazing how a "10 minute demo" answers more questions than 3 hours of reading posts on the internet. Most are stunned how simple the actual mechanics of burning an eprom really is. It's the actual "tuning" that is more difficult, but with some of the "aides" we have (scan tools, WB O2 sensors), even that is becoming quite easy.

I find those people that can "tune a carb" generally have the easiest time tuning eproms (once they learn the mechanics of it). In fact, the usual comment I hear is "not only is altering the spark and fuel easier and faster in the eprom, I can also control things I never could with my carb/dist AND I DON'T GET DIRTY DOING IT"!

 

GLENN, VADER,EDE, AND ANYOTHERS THAT I HAVE LEFT OUT;

Found the problem, my crank case ventliation system was hooked up wrong.. I hooked it up right and BAM....no code 32 Thank you all!