TPI conversion idle issues

[Rtcat9]

Installed TPI on a GM crate motor with Vortec heads. The idle is all over and running rich.
What is the best practice to tune for idle with lower than ideal vacuum signal 30 to 40kpa. What should i adjust and in what order if any.

[Six_Shooter]

30 KPA is pretty decent for idle, 40 KPA is not extremely low either.

Are you using a Vortec base (lower intake)?

[Rtcat9]

yes expensive little bugger

[JeepsAndGuns]

The 401 in my jeep idles at around map 49-50. No ammount of fuel or timing adjustment has been able to get it any better. But it idles just fine.

Have you checked for vaccume leaks?

[gregs78cam]

This is how I did my Camaro. Go to your spark advance table and make all the cells that it is idling in the same, so as to get the timing rock solid. Then go back and forth between SA and Idle VE adding or removing, to get the highest vacuum (lowest Kpa) while watching the IAC counts to make sure you haven't bottomed it out. If you do get to 0 IAC steps, then close the throttle blades a little, and restart the process. Once you reach max vacuum bring the timing back 2-4 degrees. Lastly try adjusting VE to get around 14.7 on a WBO2, if the engine likes it cool, if not put it back to what it likes.

[Rtcat9]

The 401 in my jeep idles at around map 49-50. No ammount of fuel or timing adjustment has been able to get it any better. But it idles just fine.

Have you checked for vaccume leaks?

No vacuum leaks just trying to tune for the vacuum i have

[Rtcat9]

I have locked out the timing but i am still having trouble with it idling in gear or park. It is not telling me for certian it wants more or less fuel just yet.

[Rtcat9]

I am using a 1 wire alt and i find i should adjust injector PW correction VS battery voltage to help with idle surging. any thoughts?

[Six_Shooter]

Replace the 1 wire alternator with a proper externally excited alternator. You will most likely have idling issues using a 1 wire alternator, due to large changes in charge voltage.

What are you using to monitor fuel? You should be able to get the car to idle around 14.7:1, if not a little leaner. USually using a rich idle, while wasting fuel, and possibly washing down the cylinders, will provide a more stable idle. If you need to richen it up to around mid 13 AFR or so, and start adjusting timing to get get it to lean out and smooth idle, while slowly reducing idle VE (fuel), to get everything to work together, going back and forth on VE and spark. You may also need to make adjustments to other parameters, to get other items, such as IAC or error correction to be less or more responsive.

You may also need to adjust injector comp tables, if you are using different injectors than the ECM was using stock.

What ECM and mask (code) are you using?

[Rtcat9]

730 with $8d This a howell unit that i purchesed for my dads street rod used. The car had the 1 wire alt allready. i am using TP for datalogging and burn. 22lbs injectors i think.

[Six_Shooter]

Ok, so you're using the NBO2 sensor to monitor fuel ratio? If so, it's not real reliable, since the transfer function is not a linear slope, there's little change at either end of the range with a sharp drop (or incline, depending on your perspective) between rich and lean.

I would swap out the 1 wire alternator, in every EFI application I have seen the 1 wire alternator proved to be an issue.

There is a battery voltage compensation table for the injectors located at 0x3FA, if you are not using the GM injectors, you may need to adjust this table for a smooth idle. It adds pulse width to the base PW, dependent on battery voltage. Some injectors will be slower to respond at lower voltages and so more PW has to be added to compensate to get a smooth idle. Ford injectors seem to be particularly sensitive in this area.

Vortec heads also seem to be very sensitive to timing. There should be a bin or two around here, that have been tuned for use with Vortec heads, that could give you an idea of what changes are needed.

What are you using for vacuum hose to the MAP sensor? If it is really soft, the hose can actually collapse under vacuum, and cause an erratic signal, that can cause all sorts of problems, especially idle issues.

Where is your coolant temp sensor installed?

Can you post any pictures of your set-up, sometimes seeing how something is installed can help pinpoint any possible mechanical issues, to be corrected before they cause tuning issues. It's nearly impossible to tune around mechanical problems. Believe me, I've tried. lol

[Rtcat9]

I have also increased the injector pulse width correction vs battery voltage i seen a big change with that while looking at BLMS. Yes i am using a NB O2
The Map is attached with 2" of hose direct to the port not much chance of sucking close. I have been able to get a idle but it will still die sometimes when put in drive. It also dies when i come to a stop unless i 2 foot it till it takes over. I have taken all the timing out for when throttle is closed and think that will help the stop issue.I also have knock at about 2000rpm. i have only lowered the complete timing table to try and help the idle25022503

[Rtcat9]

Ok i have got it to idle pretty good in gear and out but now i cannot scan the computer with my scanner for some reason. i can still data log with TP. Is there a way to clear codes with TP?

[PJG1173]

I think there is a mode you can set in the adx to clear codes. not 100% on that though. nice looking setup btw.

[EagleMark]

If the ADX was built completly you can edit definition and cahnge a setting to clear codes, if not disconnect battrey.

Just some ideas for you with this purdy engine conversion.
1. One wire altenators suck for EFI.
2. is that tha correct MAP for this engine?
3. I did not see CTS, is it in proper location?
4. Where's the coil? Spark plug wires near EFI wires are a bad thing and can not be tuned out...
5. Do you have a VSS hooked up?

You should not be having this much trouble making this run with that vacuum. Have you checked fuel pressure?

Did I mention one wire altenators suck for EFI? :rockon:

Look at log when engine is started and running cold, what is voltage? POOF! One wire altenators suck for EFI. Now rev the piss out of engine till altenator starts to charge, does it run better? Is it still charging? EFI likes steady voltage!

Nice looking engine bay, when you get er running right lets see rest of the rod! :thumbsup:

[Rtcat9]

1 i hear ya on the 1 wire but so far cold or warm it runs 13.7 to 13.9 even with the lights on in gear.
2 Not sure
3 yes the The cts is mounted in the front of the manifold
4 coil is mounted behind driverside head and all efi wires com in from the pass side
5 no vss just yet. I have just found out i can tap into the dakota digital speedo
6 fuel pressure is 39 with reg connected to vacuum and 45 with no vacuum


I think my biggest problem is Timing at idle and definatly at speed with ping that i get above 2000rpms.
The car currently idles in gear and drives but when coming to a stop the idle goes down to 600 then recovers to 725 which is what i have set it to.
In what order is the timing applied = base+blah blah blah = final timing or how do i use the timing as if it had just a mech and vacuum advance dizzy

[EagleMark]

OK I will retract one wire altenators suck with EFI. I have never seen one do that!

Fuel pressure should be closer to 43.5 vacuum applied and 48-49 without, so your way short on fuel.

Your pinging at 2000 RPM and your idle issues are probably both the same issue. No VSS! It sees no MPH so your running on the idle spark table, IAC logic has no idea it has to do anything to keep engine running because in it's mind the car has never moved...

How many codes are set?

Hope someone can identify the MAP sensor in his photos because it's not like anything I have seen. So it to may be an issue?

[Six_Shooter]

Stock GM MPFI fuel pressure up to between 1998 and 2003 is 43.5, without VAC reference. Pressure will be lower when vac is applied.

That is just a later model MAP sensor, they work fine in place of the earlier, larger version.

[Rtcat9]

27112712 Here are some pics of the car. i am still working on the idle issues that happen when coming to a stop. Some one has said that in a stock config they resricted the vacuum line for the power booster. Does any one know to size they resricted it? The current line is 5/16 ID.

[EagleMark]

I had to re-read through as it's been awhile... if you really think it's the booster then block it and carefully go for a drive. I don't think that is it since you don't have VSS IIRC?

Maybe post your bin, ADX and XDF and we can help you diagnose.

[Rtcat9]

yes you are correct still no vss but i am getting a spike in the map to 80 kpa when the brakes are applied and it seems to richen the idle and can't burn it off before the light changes. I am working on getting the vss hooked up. I did not think of disconnecting the vacuum line i will try it and see what happens.

[EagleMark]

i am getting a spike in the map to 80 kpa when the brakes are applied .I think you found it! Have you checked the one way valve on brake booster? Plugs into booster and has vacuum line attached.

Never heard of the limiting diameter of hose, but that may do the trick? I don't know much about brake booster specs. Would be easy to cut a short piece of metal or plastic tubing with correct OD and ID to slip in line before one way valve.

[EagleMark]

I did not think of disconnecting the vacuum line i will try it and see what happens.Remember I said carefully! Have you ever driven a power brake vehicle with bad/diconnected booster? Braking takes major amount of pressure and has long lag time. Be careful, that car is way to sweet to mess up.

[Six_Shooter]

Get a VSS installed, before doing anything else. Stalling when coming to a stop is one symptom of a bad or missing VSS signal.

[Rtcat9]

there is no valve in the fitting to the booster. manual brakes, i remember them from years past and just add drums front and rear and just say whoaoaoaoaoao till they stop or overheat. I am not stalling at the light but close to it while the computer figures it out. sounds like i need to move faster on the vss hookup

[EagleMark]

there is no valve in the fitting to the booster. manual brakesD'oh! :homer:

[jameslleary]

Dunno if you have the timing figured out yet, but an LT1 Corvette/ F body SA table would be close for that car, since the Vortec and LT1 heads are the same, with the exception of the cooling passages.

[Rtcat9]

timing is another story i am working on but i still need to confirm some engine settings like if the used balancer has spun the inertia ring and giving false readings with a timing lite. I have pretty much locked out the timing to help that out till i get to it.