I have been battling with a TPI conversion for nearly 2 months....

Chevy 350
92 Speed Density TPI
Custom PROM by: Jims Performance
Custom Harness
Mild Extreme 4x4 cam (dont have the specs with me 270 Dur.?)

First off thanks to TPIJEEP for the most excellent tech that could be imagined.

Here is what I have:

My motor is wanting to run very rich, for some reason the timing is not acting right. By not right I mean it wants to run correctly at around 30 deg. of timing for it to get the vacumn and run where it should. I have checked TDC#1 of the timing marks and they are on "0". This was just to make sure that I had the right timing marks. It seems to me that the system is for some reason battling with the motor and retarding the timing and throwing alot of fuel to it... I found out that I had the wrong knock sensor and it was throwing a code for that. I changed that knock sensor and the code went away but the performance was still the same? I drove it for about 8-10 miles and the headers were glowing pretty red.

I have checked: Compression, valves, cam, dist, no codes, new wires, new dist., new IAC, new knock....etc. As far as mechanical testing I have done everything!

Does anyone in INDIANA have or know of someone that has done a TPI conversion that I could get some help from... I would like to either look at their setup or get some hands on help. I am located in southern, IN but will travel.

Please any ideas you may have throw them out!!!

Originally posted by bigjeepinYJ


Mild Extreme 4x4 cam (dont have the specs with me 270 Dur.?)

First off thanks to TPIJEEP :D :D for the most excellent tech that could be imagined.



Okay write this down.. your cams specs..

Comp Extreme 4x4 262/270 .462/.480 111 degree lobe sep... Get back on IM and contact me.. let me know what you found out..

Did you check your fuel pressure? Maybe the return is restricted.

His fuel pressure is perfect, 41 psi. Compression across all cylinders is within 3 lbs. Cam is installed correctly, all sensors are working and no codes are being thrown..

Check all the grounds then check them again. Is it a 7730 ECM? then try the factory MEMCAL GM#16151348. The comp extreme4x4 cam is not very computer friendly - you really need a cam with 114-116 lobe centers or you will have to tweak the eprom yourself to ever get it right (see AKMCables (http://www.akmcables.com) for tools and more links). Use the MEMCAL above as the baseline for modifications.

Of course you do have this ALDL monitor (http://pweb.de.uu.net/pr-meyer.h/aldl.htm) proggy right?

wouldn't glowing headers indicate a lean, hot condition.. and did u reset the ecm after replacing the knock sensor..?

I put a TPI 305 in my FJ40 and fought with a lot of issues too... First, since you have checked TDC and it's right, have you:

degreed the cam? I rebuild the motor on mine and the damn keyways in the timing chain were mis ground on one set I installed. Did not like to run unless I had LOTS of advance...

Check and make sure the memcal you have is for a V8.

What kind of injectors are you using? The injector drivers for the TPI are high impedance, and if you installed low impedance ones, the two injector drivers might be bad... Get a injector noid light and make sure they are pulsing, not staying lit all the time...

No codes being thrown doesnt mean alot...if you dont know for a fact that non of the code flags were disabled... You can, while programming the .bin file to be loaded into the eprom disable the trouble codes for any of the numerous ones, so even if that problem exists, no codes will be shown.

Since the computer is running in open loop mode since it is not warmed up, it is possible there is a problem with the eprom .bin file.



Pull the mem-cal and check if the "chip" is a 27c256... I have heard of companies burning the wrong prom, and then the engine runs on the netre, which is the bank of resisitors on the memcal under the clear gooey coating...and it wont run well at all, PARTICULARY if the engine is different than stock.

-Brett

Originally posted by cruiserbrett
I put a TPI 305 in my FJ40 and fought with a lot of issues too... First, since you have checked TDC and it's right, have you:

degreed the cam? I rebuild the motor on mine and the damn keyways in the timing chain were mis ground on one set I installed. Did not like to run unless I had LOTS of advance...

Check and make sure the memcal you have is for a V8.

What kind of injectors are you using? The injector drivers for the TPI are high impedance, and if you installed low impedance ones, the two injector drivers might be bad... Get a injector noid light and make sure they are pulsing, not staying lit all the time...

No codes being thrown doesnt mean alot...if you dont know for a fact that non of the code flags were disabled... You can, while programming the .bin file to be loaded into the eprom disable the trouble codes for any of the numerous ones, so even if that problem exists, no codes will be shown.

Since the computer is running in open loop mode since it is not warmed up, it is possible there is a problem with the eprom .bin file.



Pull the mem-cal and check if the "chip" is a 27c256... I have heard of companies burning the wrong prom, and then the engine runs on the netre, which is the bank of resisitors on the memcal under the clear gooey coating...and it wont run well at all, PARTICULARY if the engine is different than stock.

-Brett
Just thought that I would bring this back up sorry about missing the last post...

I have checked everything that is listed above. I am too the point that the cam is not computer friendly due to the low vacumm that is produced by this baby. I am only getting 14-15 Hg at idle which is send a 2 V reading throught the map at idle to the computer which I assume is where the loading and fouling of the plugs is coming from.

Since.... When I change (more than once) the plugs it will run fine for a few minutes. And at one point I changed the plugs and immediatly took it for a drive and it ran well at RPM's around 2500. So it is buring the fuel while not have the time to fould the plugs around idle.

So that is the update.... Jims Performance made the chip so and I think that it is correct I have sent it back and he is going to send me some chips back to work with....

Thanks for the help!