Car is an 85 IROC, swapped in L98 350 from F-Body, all 85 controls, TPI in place, stock PROM etc.

So I calm down this morning, take a breather and go back out. I ended up using a white paint marker so I could see the timing tab better, and I set the timing to right at 6 degrees BTDC.....done.


Also, to eliminate the EGR as the culprit, I just unplugged the the vacuum lines coming from the sensor / solenoid and removed it. I couldn't figure out for the life of me where the 2nd hard vacuum line went, one went to the EGR valve.....where the hell does the other one go?

I set the minimum air setting on the IAC, getting a nice smooth idle at @550 RPM in gear....next.

I set the TPS to .6v at closed throttle and it goes a hair over 4.0v at WOT.......next.


I went ahead and replaced the knock sensor with one for a 5.7 '87 Camaro. At the same time I replaced the fuel pump relay, since it's coming apart anyway......

Since I had a backfire and stutter every now and then, I bit the bullet and replaced the ignition module. It looked to be the original GM unit


So now the car is PURRING at idle in Park and in gear......SMOOTH...... I'm all happy...
so I go for a test drive.


Though I got rid of the problem, then it got spark knock AGAIN!!!!!??????

Again, it seems intermittent......sometimes it does it, sometimes it doesn't.....and to top it all off... if you floor it, it will backfire, and stutter. I let off a backfire so loud a minute ago, I just know somebody called the cops thinking somebody was shooting at 'em.

So I head back to the house, ready to kill somebody........






Here's what's been replaced / performed :

- New dist cap and rotor
- Ignition module
- Spark plugs
- Spark plug wires
- Knock sensor
- Fuel Pump relay
- IAC adjusted per specs
- Timing set 6 degrees BTDC
- TPS adjusted to .6v closed, 4.0v WOT


Where do I go from here? At this point, I'm looking towards the fuel pump, ESC module, or the distributor itself.

After I get back from vacation next week ( leave in the morning ) I'm going to get a fuel pressure gauge on the car so I can watch the pressure, hopefully I can find one with a long enough hose so I can see it while I'm driving....

If the gauge doesn't point towards the fuel pump, does anybody have the spec on how to test the ESC module? My 85 Helms was paid for first of this week, just hasn't gotten here yet........OF COURSE.....I'm sure it will arrive the day after I leave for Florida.......

 

You dont want to be running that 350 on the 85 (870) ecm, 85 never had a tpi 350 and so your ECM is certainly not expecting one. The ESC module and knock sensor need to be correctly matched so the module could possibly help, but before going too deep and too far I'd get yourself a '165 ecm a memcal, and an ESC module, put that in and you'll likely find your problem solved. Not to mention when/if you ever get to tuning you'll actually be able to do something usefull instead of monkey'n with the virtually worthless 870 ecm.


What injectors did you put in with it?

I have done the 870-165 swap, if you need information or anything let me know.

 

Just did the same thing to mine a few months ago...

The other line goes to the throttlebody, it hooks to a rubber T fitting and plugs up under the TB, the other end of the T goes to the Evap cannister.


Sounds like you are running quite lean, are you using the 19 lb injectors from the 305?


I didn't like the idea of a temp installed pressure guage so I got a Cyberdyne digital guage and a 2 guage A pillar pod. Now I can watch the FP whenever I want.

As TPI_ROC said, get a 165 ECM and memcal, it is an easy swap to do, took me maybe 4 hours (didn't use the "cheap" crimp on splices), I took the time to strip insulation and solider all of the connections. Also the "new" relays you add don't have to be put in the engine compartment, I mounted mine to the metal bracket that the MAS module was mounted to.