Depending on what cam you have your vacume readings sound very low. And the 6-8 at idle and then going up to 10-14 are right as far as the trend goes is correct. However 10-14 at revs much any above idle should climb considerably. I would say you have a vacume leak. I would recommend a compression test to tell if a cyl is loosing vacume by way of a valve remaining open. Also make sure your vacume gauge is good and the test hose/connection isn't leaking and it's a good source. Also check the intake for lose fasteners. The intake gasket could need retightened or the gasket is leaking. I had a intake gasket leaking and caused fuel to enter the cylinders. Also remember the computer can only see electrical faults on sensors or sensors out of limits. If it's mechanical problem like a leaking gasket or valve adjustement it won't see it hence no code. The vacume being 6 at idle and 10 at rpms could fool the system into thinking "I'm under load and I need more fuel". The vacume should climb above 10 at cruise rpm or it'll do just what your experiencing and run rich all the time. Double check the vacume readings and compression check. With that much fuel in the cylinders washing the rings with too much running could be a concern. You may have to get some help and start tearing things back down if no sensors show out of limits with a scan tool. Then you'll need to start eliminating mechanical items. Keep posting results and good luck.

 

Compression test sounds like a good idea, I will definetly try and do that tommorrow. The vacuum test seems to be highly inaccurate cuz for one I can't get the car to operating temps cuz its dumping in way to much fuel to run the engine for more than a couple minutes and also I can't get the engine to idle at all or to even sit at a decent RPM (below 2,000). What kind of compression numbers should I expect if the valves are adjusted properly and everything is right with stock 10.5:1 pistons and the engine COLD (everything not sealing as well as it should, hence lower numbers)??

 

Let me offer you a suggestion..... moderator style. Do NOT test the language filter. Its there for a purpose. Please do not abuse it.
With or without the vacuum compensation line attached to the FPR? That's low for no vacuum, OK for having the vacuum line attached.



An erratic TPS can make the ECM think the throttle is being opened, and cause it to richen the mixture, just like the accelerator valve on a carb.


You can't test vacuum that way.... the 14"Hg may simply be the result of the throttle snapping closed after you "blipped" the throttle. It wouldn't be unusual to see more the 20"Hg under closed throttle decel.

If the Opti drive shaft is off by one tooth of the splines, it would still run, just not smoothly.

Look at the elements of the fuel calculation equation for a speed-density setup.... the chip has to have the correct displacement programmed in, the RPM must be correct, the VE tables need to be programmed correctly, the IAT and MAP must be correct. Those element allow the ECM to calculate the mass air flow rate. Then it needs to calculate the fuel requirement using the hard-coded A/F ratio, and translate that mass fuel flow requirement into a pulse width using the injector constants and offsets.

Since you are running open loop, the contribution of the block learn multipliers should be "0"d out. While the stoichiometric A/F ratio is hard coded, in the ECM, there are A/F ratio modifiers that depend on things like the ECT and TPS readings. And, since the VE tables are dependant on MAP, that too is suspect.

It would seem to me that getting a good scan software on there, and logging the conditions that exist while its running so poorly would at least allow you to rule out the things I mentioned, one by one. A good data log will have all the info that I mentioned as affecting the fueling.

Have you checked the injectors for leakage? A simple as pulling the rails up and turning the key to prime the pump.

 

Injineer seems to have a much better handle on the system than I do. I would recommend to check the TPS like he said. Also look and feel by hand for obvious things like wiring/plugs pinched/broken. I recommend write down all the possible causes in most probable order and even if you suspect they're ok they must be physically eliminated one by one. I've seen a opti a tooth off and it caused that car to run like it's out of time or run hardly at all but not excessively rich. So that may be something lower on the list. If all the plugs look the same ( i guess you have looked at all after cleaning run and remove) then my guess is your ignition is ok and the problem is air or fuel metering. Check the things injeneer mentioned and also check wiring to and from suspected sensors with an ohm meter for shorts to each other or to ground. The compressions readings I am not 100% sure so look in your manual but it should be somewhere around 100 and the lowest cylinder can't usually be more than 5-10% lower than the highest. I would look/R&R the TPS and somehow get a realtime scan tool to give you a direction. After that check wiring. After that shotgun some parts/sensors with known good ones. After that a teardown to physically check/reck items will be in order.

 

Datalogging cables cost less than $40 bucks now.. You really ought to invest in it.

I had a guy killing me over a tune that has been "fouling out plugs" and just running terrible.. He sent me a 15 minute log and right away I spotted a IAT sensor sitting on -34 degrees C. That IAT never tripped a service engine soon light.

Other than that its a strong possiblity that there could be somethign wrong with the tune.. I mean these speeddensity cars are not as easy to tune as MAF cars.. The fuel (VE) tables change per stroke per rod per injector size, per cam, per head, etc.. A difference in anyone of these variables needs a change in the main fuel table as well as the constants that control them. whereas the MAF tunes can be set for the injector, drop a generic table in here and there and be done with it.

 

damn, I didn't realize the datalogging cables were that cheap.. I am not too familiar of how all this works with datalogging... Do you just buy the cable and hook it up and it records everything that your car does and then you can just send that to whomever tuned the car? What does the datalogging cable connect to exactly, a laptop?? If it hooks up to a laptop, what software do I need to run it? This sounds like a good idea, just not too sure of how it works... will I also need a scanner?

 

I will check the TPS tonite, and if I have time do the compression test tonite, otherwise i'll just do that tommorrow, that should atleast give me an idea of whether there is a problem with leaking valves, since the vaccuum test seems to be highly inaccurate due to the fact that the car won't even idle and I am also going by what my friend who knows nothing about cars said he saw, not what I saw.

 

The vaccuum compensation line is attached, so I guess that fuel pressure is normal then..


I will check it tonite with a voltameter.


yeah, I know, a vaccuum test it near impossible to do accurately since the car won't idle by itself at all and I am going by what my friend says he saw, which truely doesnt mean anything, cuz when the needle dropped to 6-8"HG, that could've very well have been right as I hit the throttle, cuz I was opening the throttle less then every other second to keep it running.


Also, when it comes to testing the MAP, haven't I essentially done the samething as what you would accomplish with a scanner by testing them with a voltameter by testing the green wire with the car in the "on" position but off and then with it running (this, again someone had to tell me what the volts were, at idle)

For the IAT, and ECT, I just simply replaced the sensors with new sensors and I tested the mating connectors with the voltmeter to ensure that there was atleast 5.0 volts running throug the positive on the connectors to rule those 2 sensors out. I will do the same with the TPS in a minute here.

Only thing I can think of is getting something that could log all of these and send it to Ion and have him look at it to tell me if any of these are off...

Can you tell me more about how exactly this datalogging thing works? Does it hook up to a laptop and you just have to buy a cable and software? How would I have any clue to anything is programmed correct?... I don't know much about tuning a ECM, which is why I paid to have it done.

Nope, but I did swap from the 42 lb/hr injectors back to the known good stock 22 lb/hr injectors.. Whats kindof unbelievable about all of this is that the tuning is for 42 lb/hr SVO injectors (thus leaning out the injectors since they are WAY to big) and I am running the stock 22 lb/hr injectors, I would've figured that would mean that I should be running lean if anything, which is what doesn't make a ton of sense.

 

OK, I went ahead and check the TPS with a voltmeter, at idle it was at 1.08 and at WOT 4.34... So its only ~.15 volts less at idle and WOT than the haynes manual specifies where it should.

For the compression test I got the following results (the test was done while the engine was COLD)

Cylinder:
1- 205
2- skipped this one, its was too much of a pain, theres not enough room for that hose on the passenger side and this would've taken forever
3- 205
4- 215
5- 205
6- Also skipped this one... even getting this plug is a task, no way that hose and fitting were gonna fit in there.
7- 205
8- 200

I also just cranked it until the needle moved three times... Numbers continued to increase if I cranked it until the needle moved four or five times but I didn't record those results cuz i'm pretty sure your only suppose to stop after the third time the needle kicks. I also did the compression test with the ECM BAT fuse out (no extra fuel spraying on the cylinders increasing numbers as you go along).

How do those numbers look? I have no clue to where they should be, but I suppose if the valves are leaking due to improper valve lash adjustment, they are all adjusted to the close to the same amount since the numbers are relatively close, On shbox's website he says that the lowest cylinder should not less than 70% of the highest cylinder ... Not too sure if there is a problem with valves leaking though, cuz once I did the test on each cylinder, the pressure on the gauge was dropping very slowly, I would think that the pressure would drop very fast if the valves were to remain open..

EDIT: I just check the haynes manual, it says cylinder pressure should be 100 PSI minimum... WTF, why would mine be over a 100 PSI higher than they should be? Could it be cuz there is fuel from just sitting on top of the pistons (I accidently primed it, not too much before I did the test)?

 

dont mean to hijack the thread but where can i get one of the cables that cheap?

 

The TPS voltage at closed throttle should be in the range of 0.20 - 0.90 Volts. Anything over 1.0V is not good, and should be corrected. Most people like to see a reading in the range of 0.50 - 0.67 Volts, but it shouldn't matter, as long as its below 0.90V.

Similarly, the EXACT WOT voltage is not important. It should be about 4V higher than the closed throttle voltage, but al long as its over 4.oV, the PCM can handle it.

But your closed throttle voltage is wrong and you need to find out why.

Manuals like the Haynes use a "generic" compression test procedure - one size fits all. The actual pressure level isn't all that important, its the variation from cylinder to cylinder that matters. They probably also tell you that anything within a 20-25% range is OK, and I would not want an engine with that much variation.

The exact level will depend on how hot the engine was, how many times you cranked it, how far you had the throttle blades blocked open, how strong the battery was, how wet the cylinder walls are, and as you appear to find out, how much fuel you dumped in it. I suspect you had a good shot of fuel in each cylinder to get the values you got.

But it isn't important whether its 180psi or 205psi... the important thing is that all the cylinders are similar. ut its not good to load it up with fuel, because wet cylinder walls may raise the pressures.

 

That's weird... the haynes manual says that the idle value should be between 1.20-1.60 and that WOT should be between 4.5-5.0 volts. The values you are giving are with the car off and the ignition in the ON position, correct? Why would the idle value be .18 volts too high? Bad TPS? Also would that extra .18 volts be enough to cause my car to be run EXTREMELY rich? It does dump a lot of fuel in at lower rpms, but it also dumps a LOT of fuel in when revving the motor..

Sounds like compression is pretty good then judging by what you said, and it doesn't seem like improper valve adjustments would be the cause for it running rich then.

 

Where can I get one of these cables? How does this work exactly, what software do I need to get it to log everything that is happening when the car is running to my laptop (i'm assuming it hooks up to a laptop)?

Since you mention that, I have a feeling that tuning may be an issue, cuz I remember when Ion burned the orginal chip that my injectors were too big (42 lb/hr) and that it was still going to run a bit rich, he said that he leaned it out a bit didn't want to lean it out too much. And now that you mention how exact the main fuel table needs too be and that the main fuel table and everything else needs to change for every variable, kindof suggest that maybe a somewhat generic table was just dropped in and worked with cuz i'm sure tuning with the 42# injectors without actually having the car there wasn't all that simple.

 

42's aren't bad.. I actually ran them in my hotcamed automatic 350 car for a few months because thats all I had. I've got 65's in my 93 now and it will pass emimissions with a 350 and 210/220 cam It idles very clean.. You might smell exhaust (not rich, but exhaust) just from the camshaft.

Get a cable from aldlcable.com and send the scan to someone who can read it.. You may find that the IAT sensor or harness is bad.. Replacing is not the way to fix problems like that.. the wya to fix them is to locate the problem directly.

 

Actually, after reading your TPS guide on your page, I noticed that you are testing the voltage at the sensor... drilling out the holes in the TPS sensor. I tested it about 6 inches down on the dark blue wire, cuz it was easier to get the lead from the voltmeter on there and I just used metal on the car for a ground, like how hayes does it. Not sure if it makes a huge difference, but that might the cause for the variation in voltage, nonetheless the increase was over 4 volts from idle to WOT.