morepowerjoe

Hey guys on a 87 TPI MAF System how far can you go before you need a custom chip to compensate for mods. I have a 305 with headers, 10.1 compression, hyperjunk chip, and a comp cam
http://www.compcams.com/Cam_Specs/Ca...?csid=194&sb=2
It just won't idle right after it's warmed up. It mainly has a unpredictable but frequent surge. Does anyone know if the cam and injectors would be causing this. The engine and almost everything is new, and I have checked and adjusted everything I can think of. Thanks.

vetteoz

iTrader: (13)

Stock 305 had 19lb so it would be running rich unless the tune is modified to suit larger injectors.
Does it sell rich at idle?
MAF ECM will self adjust to extra airflow ( within reason) from cam / exh mods but not larger injectors.

BadSS

Cam is fine. You need to get the equipment to burn your own chips, but if you can find a 350 chip cheap,, that will match the injectors and it should run decent enough to get you by. Either that or put the 305 injectors back in.

morepowerjoe

I never thought about putting in a 350 chip. Thanks. As for it smelling rich, I can't tell. Do one of you know how to look up the chip numbers to see what they are? Cause I have a few but I don't know what engines they are for.

vetteoz

iTrader: (13)

Memcal has 4 letter ID code ( Broadcast code ) on it

Select the year at bottom of page
http://www.chevythunder.com/prom_bcc_1987.htm

Be aware another stock memcal may have a different VATS on it to your car so you may have to disable VATS to use it

morepowerjoe

vetteoz, Thanks a million, I've needed a chart like that for so long. Now I know I have a 88 350 chip. I'll put it in tomorrow and see what happens.

Orr89RocZ

iTrader: (20)

yeah that system should run that setup but the injectors will make it abit richer than needed. Have you tried to adjust base timing a few degrees? Cam may want abit more timing. Also can try giving the throttle screw abit more adjustment for slightly higher idle rpm to help stabilize things, but true chip tune with these adjustments will be best bet.

morepowerjoe

I used to really want to buy the stuff and try burning myself but I just kinda chickened out. I really need to though. I have two 86's and a 91'. It's not like it would be a bad investment for me. And the base timing, it definetly wants plus 6 or so. But even my stock 91 TBI has to be at 6 to run right. You know I forgot to say I have 10.1 compression too. But that wouldn't really hurt much would it? Thanks again guys for your help.

Orr89RocZ

iTrader: (20)

Its just gonna want more fuel than stock, but it should run ok on stock tune

morepowerjoe

Ok let me tell you guys what happened. I've had a hyperjunk chip in it, for a 305. I put the 350 chip in and it wouldn't start. No spark. So I put a stock 305 chip in and it starts fine. I pull it out put the 350 chip back in and it will start one time. Turn it off and try to re-start and no spark again. Really strange to me. But when it does start, I can adjust things out ok, and get it to idle a lot better then the other chips, But still rough. Anybody know why the 350 chip starts only one time? Thanks.

Orr89RocZ

iTrader: (20)

It doesnt spark at all? Or will it spark and not fire?

Is VATS disabled?

morepowerjoe

Well I'm just assuming there's no spark because I checked the fuel pressure and it was good. And the chips are all pre 88'. They didn't come out with vats on f-bodies until 89' right?

vetteoz

iTrader: (13)

As I noted in post# 5, the VATS may be different on another (any ) memcal .
VATS takes out the injectors and starter; the fuel pump will still run.
Vettes got VATS in '86 ; when did it start on F-Bodies ?

morepowerjoe

May be the 350 memcal does has vats because it only starts if I pull out one of the other memcals and put it in real quick. May be the ecm thinks it still has the other memcal, I don't know. And for all I know it could be a vette memcal. But I do know once I turn it off, it won't re-start. So it does sound like the injectors aren't spraying or there's no spark, but the starter does work. Either way it did run a little better, so I'm sure you guys are right, I just need a memcal for the mods that I have done to get it really running like it should be. Is that pcm for less a good place?

vetteoz

iTrader: (13)

$150 gets you a chip with any mods you like;
delete VATS / EGR /AIR , change fan on / off temp , remove the cold start injector , etc

http://www.pcmforless.com/index.php?...id=2&Itemid=43

morepowerjoe

I'm gonna get a chip from there real soon. I'll let you guys know what happened.

Street Lethal

iTrader: (16)

You need to check your BLM's, as this will tell you where you are in terms of being rich, or being lean. My '90 GTA is running 24-lb LT1 injectors with a bone stock 305, and it idles flawlessly, even with a 110 BLM (very rich), with or without a load, so it's not your injectors being too large. If anything, with more duration in that camshaft, and 10:1 compression, you might needa tad more fuel that what your already getting. Do you have an adjustable fuel regulator? If so, crank it up in incriments until she smooths outa little. Again though, check your BLM's, as it will eliminate all of the guess work....

Orr89RocZ

iTrader: (20)

its possible the startup crank fuel tables of the 350 are not working with the 305. Not sure of the difference between the two but that could create issues at startup. It has plagued me in the past and still does

morepowerjoe

What's BLM's?

Street Lethal

iTrader: (16)

BLM (Block Learn Mode) is your long term fuel adjustment, and INT (Integrator) is your short term fuel adjustment, the two work hand in hand within a cell structure designed to optimize your AFR (air fuel ratio), with the value of 128 being stoich (14.7). Once the engine reaches normal operating temperature, the ECM will add to the INT (short term fuel adjustment) in small incriments until the O2 sensor (the O2 sensor is a switch) goes above a specified threshold, the ECM then immediately learns that the AFR is now rich because the cell value will indicate a number lower than 128, so it begins subtracting fuel until the O2 sensor goes below it's specified threshold, in which it then learns that the AFR is too lean because the cell value is higher than 128. It will continually sweep back and forth trying to maintain an average of 128 (14.7 AFR), and does so approximately twenty times per second. Knowing your BLM will help you to understand why your engine is struggling....

jv9999

iTrader: (1)

What Lethal said. The first thing I'd do it put a heated (3 wire) O2 sensor in it so it's running closed loop at idle. It will compensate for the bigger injectors if the O2 is up to temp (up to a limit).

transam85dudeman

the screen for the maf fell off the re-manufactured unit. i run one screen on the maf, the intake of maf. the output of the maf is missing. its ok i think, as long as the first screen is on. muahah

morepowerjoe

In order to look at my blm's I'm assuming I would need memcal burning stuff right?
And for that heated o2 sensor, what's involed in that? I've always heard that is the way to go.

morepowerjoe

No I don't have an adjustable regulator, do you think I really need one? Yeah I was thinking when I bought the injectors it would be ok. I think for grins I'm gonna put the stock injectors back in just to see if that's really my problem. I have a feeling it might not be. I have about 5grand in this engine that won't run worth *hit. So I hate to keep dumping money at it at this point you know. Do you or anyone else know how to identify a 305 injector from a 350? I have two sets. I bought a lot of used parts and don't really trust much of what people tell you when thier selling you something. I'm also going to readjust my valve lash just to be safe too.

vetteoz

iTrader: (13)

Not to datalog.
This cable
http://www.aldlcable.com/
and this program TunerPro RT
http://tunerpro.markmansur.com/downloadApp.htm
with a old laptop, lets you see and record what your engine is doing
You need the burning gear if you want to make your own changes to the tune

Street Lethal

iTrader: (16)

Like vetteoz pointed out, you just need an OBD1 scan tool, as this will give you your BLM's, as well as where all your other sensors stand. It will eliminate the guess work, and should be the very first thing someone buys when they run a OBD1 system. Kinda costly, yes, but I must have used mine hundreds of times, so it pays for itself in the long run. Wideband O2 sensors are good for tuning, but once your dialed in, you can remove it. I leave mine in only because I hit up the track three times a week, and I need it to monitor my AFR for boosted conditions.

They are good to have, especially since your not able to adjust injector pulse width. Your engine might want more, or less fuel, and the adjustable fuel pressure regulator will help you with that. Otherwise, you'll be changing injectors over and over again, trying to find the right size, and you'll still be second guessing yourself....

I can see the injectors being a problem if they are low impendence, or if they are simply larger than what they were advertised to be. If you have spare gaskets for the runners lying around, try it, and see what happens....

The injectors will have a number on them, post them up and I will tell you what you have....

No more than a half of turn....

morepowerjoe

The injectors. This set is old I think, it has a FJ8 on the side of the plastic.
On the other ones I think they are from a 91-92 Camaro, the have the numbers
9120 / 17086542 on the top connector side.

morepowerjoe

Can I make my own data cable somehow with a usb? And then just get the software?

Street Lethal

iTrader: (16)

The 542's are Rochester 20 pounders, a tad more than your stockers. Did you replace them with the stockers again to see what happens, and if so, what? I'm not sure where you got these injectors, but if they are used (high mileage), it is very possible that they are grounding out the ECM (injectors have internal coils, which go bad in time). But, we'll know this for sure once the stock injectors are put back in, and if the engine acts the same way....

Street Lethal

iTrader: (16)

By the way, the 542's are high impendence injectors (15.8 ohm's), same as your stockers....

morepowerjoe

The current injectors in the engine now are venom 21lb.
http://www.jegs.com/p/Venom/Venom-Hi...59823/10002/-1

I bought them new. And the used ones I don't know what the mileage is on them. But I did check the resistance in all of them a while back and they where all in spec and all the same. I don't remember exactly how, but I did it according to all data. If I did put one in that's grounding out, just to ask, would it mess up the ecu for good?

Street Lethal

iTrader: (16)

Hard to say, as I have seen some instances where the ECM went bad after replacing bad multec injectors, and other instances where the ECM was fine. Too many variables to say yay or nay. If you checked the resistance of the Venom's, and they are in spec, that is good, but now you need to check the harness individually with a noid light to make sure they are all getting signaled to fire....

morepowerjoe

You know I'm not going to take a chance with those old injectors cause I bought that ecu new. I'm just going to keep troubleshooting for now, and probably get a new memcal next week programmed for those injectors and go from there. I sure appreciate all you guys helping me out, and I'll let you know what happens next.

vetteoz

iTrader: (13)

Know anything about building electronic circuts?
Only online ALDL cable diagrams are for serial port connection which you find on older laptops

http://www.techedge.com.au/vehicle/aldl8192/8192hw.htm
http://cable.invisibill.net/

morepowerjoe

I did a little research on making that data cable. I'll just buy one.

morepowerjoe

I adjusted everything this morning back to specs. And it is actually a lot better. But the engine still shacks a lot like a big miss, but I got the surging to go away. I can touch all the injectors and feel them pulsing or something. As for power I drove it a little, and it has plenty of power, it'll roast the tires very easy. Now I'm just going to get that cable real soon to look at the data like you guys said.

morepowerjoe

Today my friend let me borrow a good scanner. It's a actron super scanner. It let me look at all the sensors in real time with the engine running.

First thing, I decided to go ahead and put those 305 stock injectors in it for the first time and see what happened. It ran a lot smoother but it's hard to get it to stop surging. It gave me a code saying fuel pump voltage pressure was to low or high and then it wouldn't start. So I charged it for a while and then it started back and I got this data out of it. I took pics of the data on my phone so I could come into the house and put it on this post but I couldn't read it to good, but here's what I got. Anyone that has the experience to look at this telling me what they think is much appreciated.

O2 CROSSCOUNTS 135
MAF(gr/S) 2110
MAT (*F) 93
O2S (?U) 679
IAC position 16
INJ PW(?S) 99 up and down from that to 110
Intagrator 120
ESC Counter 103
Exhaust O2 goes form rich to lean, back and forth
BLM 120
BLM Enabled I can't read, I think it says no
Coolant (*F) 154 (I have a 160 t-stat and a hyperjunk chip)
TPS .59
I let it run a long time and it never said closed loop. It always said open. Is that the problem and the BLM won't learn?
What would make it not go into closed loop?
And one more thing. When I was re-checking the IAC, it still had the surge, and that was strange to me because I thought the surge would be from the IAC being adjusted by the ecu. But I had it seated and unpluged.

transam85dudeman

the tps should be at .54 volts, adjust that. i was thinking about the coolant sensor but you said you installed the chip and t stat.

Street Lethal

iTrader: (16)

Your IAC counts at idle (16) are fine. Your O2 sweeps back and forth (its supposed to do that, it's a switch), and is showing 679 millivolts (14.5 AFR) and the higher the cross counts (135) the better, both are good. BLM and INT are fixed at 120 (slightly rich) because your ECM is commanding Open Loop, normal. Your TPS is a little off at idle (like mentioned above, it should be at .54 volts), but not off enough to make that much of a significant difference. The coolant though, considering the fact that you live in Texas, and you had the car idling for a very long time, should be much higher than just 154 degrees, and is more than likely your problem. When ECM's are stuck in Open Loop, the first thing you want to look for is engine temp. It could even be in that ridiculous chip for that matter. I would get a new coolant temp sensor, and if that doesn't do it, get your hands on a stock L98 chip for the time being....

morepowerjoe

I have a stock chip for it (86 305). But when I put it in it won't start. Same thing with the 88' 350 chip. Not unless they have vats on them, because it seems like the injectors aren't firing like we talked about earlier. And I don't have one of those lights. I'll try the chips again tomorrow after I charge the battery for a while and replace the temp sensor. Also the temp here right now in Texas is 50-70 where I'm at so it might be right. And for some reason the fan runs continues, I've been assuming it's because my ac stuff is unpluged.

How come the scanner didn't tell me anything about the knock sensor? Is that not apart of the diagnostics? Thanks.

vetteoz

iTrader: (13)

Only if it is activated while you had engine running.
As above if the CTS is reading low ( be it faulty or coolant temp low ) the ECM won't go into closed loop

Some background reading
http://www.aa1car.com/library/1999/cm69910.htm

Street Lethal

iTrader: (16)

That is a correct assumption. You need to jumper (loop) the AC switch that is located on the passenger side frame rail, this will stop the fan from running constant, and get you back up to normal running temperatures (get a wire of similiar gauge about five to six inches in length, strip both ends, twist both ends with your fingers, then place into both sides of the terminal's connector). O2 correction (Closed Loop) is partly enabled at around 90 degrees, but it is fully enabled at upwards of 170 degrees. Sounds like your caught in the middle somwhere because of the fan constant issue. As for VATS (passkey), as far as F-Body's are concerned, it was only used on GTA's in 1988, then later in 1989, the other models were equipped. Your going to need a noid light to make sure the injectors aren't getting pulsed w/those other chips, otherwise your just guessing....

Street Lethal

iTrader: (16)

If you do in fact have an '88 350 chip, it more than likely does have VATS written into it. You can't use it, so stop trying to. However, the '86 LB9 chip though does not have VATS written into it, and should both start and idle the engine just fine. Now, you have the stock 305 chip, and that hypertech chip to use. The first thing you want to do is get that coolant temp situation fixed by putting a jumper wire to that AC switch, then, when Closed Loop is enabled, see where you stand as far as surging is concerned. Right now, your trying to diagnose a surge when the engine has no real O2 correction. Fix the fan issue, get the engine up to a more solid 175 degrees, Closed Loop should enable (surge should go away), then check your BLM's again....

morepowerjoe

Thanks for the link. Even though I know most of it, it's nice to have a little refresher every once in a while.

And thanks street lethal for the info, I'll get that jumper in there today and get the temp up and recheck whats happening.

morepowerjoe

First thing I did was put the charged battery in. And left in the hypertech chip. Got it running and put a jumper in that ac connector. Fan stayed off until 175. That's right when it goes into closed loop. So it just goes back and for between open and closed loop, because the stat and chip actually are doing a good job at keeping it in the 174-176 range. And now we know the temp sensor works. I can get the surge to just about completely go away only with adjusting base iac, and base timing. But it will not go away at all when I try to bring the base idle below 8-900, it really wants 9-950 the most it seems like. I then tried the 305 chip again and it worked, but I can't get it to run any better. I think it's actually worse. I think those chips may be wouldn't work because the batt was low, that's all I can figure.

So is a minimum air amount of 900 too much? Or would that be just where it needs to be with the cam and compression? It seems like timing is the ultimate tuning factor for this engine. That's where I can control the surge the most by advancing it pretty high. Past the pointer, I'm thinking around 10-12 degrees. Should I try again with the hypertech chip and may be a seperate controller for the fan and get it past that open loop in 180-190 so it stays in open loop?

And does anyone know where the little wire from the alternator goes so I can double check my wiring? I need to know where it goes from the alternator to the ?.

Thanks.

Street Lethal

iTrader: (16)

Yes, Closed Loop is fully enabled at that temperature. You will see O2 readings on the scanner, but until it officially says Closed Loop, you will still be running off of a pre-configured factory tune for Open Loop. At this point, you would either need to raise your temp settings back to stock, or lower your Closed Loop (full) enable at a lower temperature in the prom....

The MAF can only compensate so much for the cam, and it needs to be fine tuned. Keeping it at 900-950 RPM is fine, it won't cause any real issues, but if you want it lower than that (800-RPM), have someone burn you a prom w/better tune....

The 305 chip will allow it to be drivable, but the tune will be way off though. The hypertech chip, and any L98 chip w/out VATS will be slightly better, but a custom one is what you need now....

Minimum RPM? No, 900 is fine....

You have the EST disconnected when setting base timing, correct? 12 degrees might be a little too much, but if your happy at that setting, just make sure she's not knocking anywhere in th RPM band, so listen carefully. The combination of both the cam and compression need to be tuned in the VE (fuel) table. I would keep it at 8 degrees for now, and have someone burn you a prom for your setup....

These are your options until you get a custom prom burned. You can run the hypertech chip (which is programmed to turn the fans on the same time Closed Loop is fully enabled), but run a 180-190 thermostat (which will essentially force the engine to keep that warm, regardless if the fan is on or not). Or, run the 305 chip (with the factory fan settings), and deal with a slightly higher RPM. Personally, if I had to wait for a chip to be burned, I would go the hypertech chip in the interim, as the tune is a little more fitting for that cam (again, just until you get a prom burned, because you need one)....

Which wire? The one on the back goes to your positive battery terminal, and the one on the side of it is for your volt gauge. Note that if the one on the back isn't (or wasn't) connected all this time, this will have an effect on the ECM....

morepowerjoe

I put the hypertech chip back in and re-adjusted everything one more time. I let it run even longer this time. It went in between open and closed loop for a while, stumbling everytime it went into closed loop and then bounced back to open. Eventually though it stayed in closed loop and ran pretty good. The temperture actually went down to the 160's and stayed there. So I don't know why it did, but it did. I put the base timing at 8, and it seems ok. Oh and yes I disconnect the est everytime I set the timing. The rpm at idle now is trying to stay between 850-900. As for that altenator wire, the one that goes to the gauges is the one I need to figure out. I have one pluged in that I think is right, at least the gauge seems like it's working, but I'll figure it out. So I think it's good for now. But like you said Street Lethal, it needs a good chip and that will probably be the next and finale piece to the puzzle.

I built this car almost two years ago. And it's been sitting every since last week. I bought it without an engine, or harness. I had to peice together everything. Boy have I learned a lot! It made me so mad for so long I couldn't stand to look at it. And now I've finally got closure. Thank you so much Street Lethal, and everyone else that helped me this week.

morepowerjoe

Now Street Lethal if you want to take a look at my next project, in a post I guess I'll call (oldsmobile TPI or TBI) you advice will be much appreciated.

rgarcia63

I bought a Pocket Romulator to emulate my chip before I started my project and never burned a chip, I piggybacked it to the ECM. I have saved alot of money and time by not having to pull the ECM out and reprogramming the chip.