i have just finished some had to be done for safety type repairs on an "86 IROC we recently got.now i can turn my attention to the TPI.i must confess that i don't know too much about it. but i want to learn. is their a web site or book i can get to help me?i suspect that i have some simple problems that a basic check over could solve. for example;the thing will not start without pressing down on theaccelerator.hot or cold.and the instant it starts it has a definite miss for about 2 or 3 revolutions. any way i hope you can help out a "new guy"
thanx,ANDYZ28

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82Z 305 w/comp 270 magnum cam,holly.TH700R4 w/B&M holeshot 2000 converter,& megashifter. 9bolt 3.27 w/1LE rear brakes 70mph@2200rpm ASE Master Tech plus L2
also recently obtained a
'69 chevelle SS396 w/Turbo 400,3.31 posi,11.0 to 1, headers,etc

 

Probably the best beginner book is TPIS's (Tuned Port Induction Specialities)'Secrets' book.

It explains the workings of the TPI engine, what the ECM and all the sensors do and has a lot of dyno results showing which mods give power improvements.

Check out their website at TPIS.COM

That's where I started after moving from carbed engines to fuel injected ones.

Hope this helps.

Jake

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9

[This message has been edited by JakeJr (edited November 25, 2000).]

 

Andy, hop on over to the tech articles on this board and read all about stuff. Read it all and you will have a good overview of stuff, then just pop through a couple posts in here and in General Tech. Also if you have a specific question, you can use the search engines. If you have a prob that you need help on, post a question and see if we can help ya!

 

i had that starting problem too, it arises once in a while depending on the gas i put in it. does it miss,miss,miss then fireup smooth? i changed the pickup coil in the cap and that helped, TPI is pretty nice intake so good luck.

-Stell


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1988 IROC 305TPI MINT!!
Mods= Accell SuperCoil, MSD 6A, Ported Plenum, No MAF Screans , K & N, 160 Thermostat+ Temp Switch, Relocated MAT, Cold Air

 

O.K. STELL 1579 & Red Devil here goes:The car appears to be bonestock 1986 Iroc Z with
305 TPI.When starting the car it acts like it
has maybe three bad plugs but after missing
three or four times, it then idles smoothly.
I believe this somehow connected to the problem, that the engine will not start without your foot pressing down on the gas.
It will eventually start when it is hot but
requires extended cranking (that is to say without your foot on the gas)but it has this
very brief miss even when hot.
Correct me if I am wrong,but I believe I should be able to start the engine while
standing outside the vehicle (foot not on gas).
Now remember fellas I know all about carburetors and ignition systems in general, so I don`t know anything about TPI systems.
Thanx ANDY Z 28

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82Z 305 w/comp 270 magnum cam,holly.TH700R4 w/B&M holeshot 2000 converter,& megashifter. 9bolt 3.27 w/1LE rear brakes 70mph@2200rpm ASE Master Tech plus L2
also recently obtained a
'69 chevelle SS396 w/Turbo 400,3.31 posi,11.0 to 1, headers,etc

 

Well, there are basically three things that have to be adjusted properly to allow the engine to fire while you're standing outside.

The Minimum air flow setting, the TPS voltage setting and the IAC count setting.

Here's the procedure:

First warm the engine til it reaches normal operating temp and is in closed loop.

Then shut down the engine and insert a paper clip or somthing similar to jump the A&B connectors on the ALDL under the driver's side of the dash (I'm assuming that's where yours is since that's where it's located on my 86 Vette). A&B are the two top right slots in the ALDL (Assembly Line Diagnostic Link) also referred to as Assembly Line Communications Link (ALCL).

Now turn the ignition key to "on" but do not start the engine. This should cause the cooling fan to come on and the ECM will send electrical pulses to the IAC motor to fully extend the pintle.

Now disconnect the IAC connector from the IAC with the ignition still on.

Turn off the ignition key and remove the jumper (paper clip).

Next, my GM manual says to be sure to disconnect the EST connection which is near the power brake booster on my car and is a single tan wire with a black stripe.

Start the engine and let it run til you're sure it's warmed up. It may be difficult to start with the IAC disconnected so you may have to depress the gas pedal to get it to run.

Adjust the minimum air flow setting by adjusting the torx head screw that's on the throttle body near the throttle/cruise/trans cables. GM sent out a revision notice that says to set the minimum air flow setting to 500 RPMS. (I'm assuming a stock engine setup).

Once this is done, shut down the engine, reconnect the IAC and EST wire. Disconnect the battery for at least 30 seconds to clear the error code that was set when the ECM detected the engine running with the EST disconnected.

Now, you'll need three pieces of wire each about 8 inches long. They need to be inserted in the TPS and TPS connector to allow you to take a voltage reading.

The TPS voltage should be .54 (+/- .075)That's the spec for my engine but you might want to check to see if yours is the same.

To adjust the voltage you'd loosen the two bolts that hold the TPS to the throttle body and rotate the TPS up or down.

You'll need a digital volt meter to make the TPS adjustment; there's no way to work around that requirement that I know of.

With the jumper wires in place, insert the probes of the voltmeter into the upper two TPS positions, set the meter to register tenths of a volt, then turn the ignition key to "on", but do not start the engine.

After the adjustments are made, drive the car immediately at normal throttle settings and at around 40 MPH so the computer and IAC can learn the new settings.

It's kind of involved for a 'first-timer' but if there's no other problem with the setup, the car should now fire the way you want it too.

There are several other reasons an engine won't fire properly; leaking or faulty injector, incorrect ignition timing, vacuum leak, on and on.

A GM service manual for your specific car will show any differences between your car and mine.

New, properly gapped plugs would be a plus.

Hope this helps,

Jake

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9

 

Thanks Jake,I'l do this procedure tomorrow. Then I will let you know how I make out.
Thanx,again ANDYZ28

 

Personally, it sounds like you have a leaking injector/FP Regulator.

The fact that you have to put foot on gas says its probably flooded with gas.

The fact that it misses for a few revolutions says that one or more plugs may be "gas fouled" from the flooded condition described above.

I noticed in your sig you are an "ASE Master Tech". I am assuming with the L2, that you are a Heavy Duty Master. If you are an Automobile Master, than this problem should not perplex you, because TPI shares the same principles of other F/I systems, wether it be Ford, Chrysler, or other GM systems.

You need to hook a fuel pressure gauge up to the fuel rail and check for leakdown.

------------------
If you live in Southeastern US, check us out!
South East Thirdgen


ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
JET AFPR,
Ported Plenum,
TB Coolant Bypass,
SSM SFC,
Boxed LCAs,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
KYB Shocks
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

 

GMTECH,yes I am an ASE Heavy Duty Master Tech
w/L2&P2. My experience is entirely with large
heavy duty diesel engines.The same ones the power large trucks down the road(if you have it,a truck brought it) these engines use mechanical fuel injectors(for pressure and delivery) and electronics (for metering).So as you can see its the same but different.
by the way i just found out that i have a much larger problem that the engine starting.
i'll post it on the trans board now.
THANX ANDYZ28

 

Hey, I know, I used to work on class eight trucks myself. Didn't like it, went to cars.
I'll check out your post on the trans board.

------------------
If you live in Southeastern US, check us out!
South East Thirdgen


ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey, 22# injectors,
JET AFPR, Ported Plenum,
TB Coolant Bypass,
SSM SFC, Boxed LCAs,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
KYB Shocks
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

 

Check out the main page of my website (see sig). The "Firebird Literature" section has several books on TPI. You can probably get most of them from Amazon.com, except for TPIS Insider Hints. You have to get that from TPIS.

------------------
1989 Formula WS6 M5
SLP cold air induction, K&N filter, TPIS modified MAF, TPIS 52mm TB w/ airfoil, Random Tech cats, SLP cat-back, TPIS AFPR, March underdrive pulley, Accel 300+ coil & 8.8mm wires, Bosch Platinum+4 plugs, Hypertech 160°F t-stat & fan switch, Hypertech Streetrunner chip, Centerforce dual-friction clutch, PST front suspension kit, PowerStop cross-drilled rotors, Porterfield Carbon Kevlar pads, Russell SS brake lines, Firehawk SZ50 EP P255/50ZR16.

G-Tech Pro measurements:
0-60 mph: 6.0 sec
212 RWHP

1/8 mile results: 9.74 sec @ 74.5 mph; 0-60 ft @ 2.35 sec; +0.46 reaction

2001 Trans Am WS6 A4
Stock

More info at website:
www.fbody.com/members/stevenmh

 

Andy, I would look into yanking your ignition module and bringing it to the parts store to have it tested. Also double check all the coil in cap stuff and make sure the carbon brush isn't toast and the ground strap in the coil head is clean. It sounds like a combination of fuel and ignition probs. and I personally like tackling the ignition first.

------------------
"The people always have some champion whom they set over them and nurse into greatness... This and no other is the root from which a tyrant springs; when he first appears he is a protector.
-Plato

 

RED DEVIL, I believe you are correct about the starting problem being a combination of both fuel and ignition. I have been paying close attention to the car when it starts lately. And I have made a couple of observations. If the engine is up to normal operating temperature,and you shut it off. Then resart with out touching the gas. It will take a realativly long cranking time,and when it does start. It just barely starts,then suddenly comes up to idle speed very smoothly.
As the weather slackens I am going to set the base idle,TPS,clean and inspent the IAC, check fuel pressure,etc. So that I can then deal with "known good conditons".
Does that sound like a plan?
By the way. What sould I pay for a complete stock GM TPI set up,air inle ducts, everything?
I noticed that you have a very thought provoking quote as your signature.So I have one for you;"place a man in conditions which only a beast can endure,and a beast he shall become" Henri David Thoreau

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82Z 305 w/comp 270 magnum cam,holly.TH700R4 w/B&M holeshot 2000 converter,& megashifter. 9bolt 3.27 w/1LE rear brakes 70mph@2200rpm ASE Master Tech plus L2
also recently obtained a
'69 chevelle SS396 w/Turbo 400,3.31 posi,11.0 to 1, headers,etc. Latest project car,'86 IROC stock 305TPI hit on left side not too bad

 

My car has a similar problem starting warm. Whenever it is cold it fires right up but when starting it warm, I have to crank it for about 5 seconds, then it stumbles like Andy's and then smoothes over. My charcoal canister is bypassed but I think the problem could be fuel pressure because once in a while when starting it cold, if I dont crank it long enough (half a crank because I get ****y), then try to start it again, it does the same as when it's warm and the fuel smell is emminent. I guess it floods easy.
As you can probably tell, I'm also new to TPI

Thanks