Gamefreakgc

I'm not so sure an advance in timing is a bad thing. Advancing timing gives more power anyway, unless you are pinging. But, I've never checked mine when its running. It'll vary based on feedback from the sensors.


About your PAIR valve, if you're idle speed is too high it'll kick on. Mine kicks on at about 1050 RPMs. As long as you know your TPS is set right then make sure your idle is around 800 or so. If it still kicks on, your TPS isn't set right, or something is holding the throttle open.


8/91 means you use the newer kind of distributor & cap and rotor.

Gevo

Gamefreak, thanks for that response. I didnt pay attention to see if when the times it is on the idle is above 1050 or so. I didnt think about that. Cant wait to get back to it.

muddmadness

Gevo...my bad sorry!!! I know how you feel, I have been over the edge a couple of times in the last 14 months. I learned a lot in that time and still continue to. I reach a point of just throwing my hands up then something happens and gives me hope. Just don't give up You are in the right place to find help that's for sure.

Gevo

Alright, got a smog check lined up for today. I am going to adjust the VAFM a couple of clicks lean before I go in.

If the timing jump (vs. gradual increase) is not an actual problem then I don't think I have any other issues to worry about before going for the smog. But, I don't really understand now how it is SUPPOSED to be, is the timing supposed to jump up 15 degrees when the TPS moves out of IDLE or increase gradually???? Without TPS plugged in it increases gradually, and with tps it jumps a bit then continues to increase gradually.

As far as the overly rich condition and backfiring, it seems the TPS sensor adjustment to it's proper place should have fixed that. Turns out after I had last set the TPS, I had adjusted my throttle body and then forgot to readjust the tps. In turn, the throttle body adjustment was just enough to throw the TPS into the "not idle" position, after which i adjusted timing to 10-degrees. So, at this point the TPS never went back into the idle position and that is how i had it last tested for smog.

I'll get to the car soon to see if the EGR valve is working as gamefreak mentioned it does around 1050 rpm.

Mudmaddness, i'm on that 'I kind of have hope' wave right now... watch the smog test crush that by the end of the day. lol

muddmadness

May the smog gods smile upon you today

Gevo

so I'm following a few threads and a video on youtube to adjust the AFM. In the video when he turned it lean which is clockwise the engine respond by dropping in rpm. I turned 4 clicks to lean I didn't notice any difference in engine speed. Should I go more? what do you guys think? Is this all trial and error? Lol

Gevo

The smog gods have crushed me.

After installing a working charcoal canister, properly adjusting the TPS, putting the old distributor back on (it was better than new) and adjusting the AFm 4 clicks lean, the results? Worse... yes, the numbers were slightly worse than before.

So, saturday morning i'm gonna drop it off at the mechanic and he seems to think he can figure it out.

However, to be honest after setting the timing properly with TPS and then today the afm adjustment to lean, I seriously felt a good amount of power come to the engine that I hadn't felt before. I mean, it runs very smoothly, idles properly, revs strong and pulls strong. Ran it around on the freeway today and held 65mph in 4th (overdrive) with NO problems. As far as the engine operation is concerned I dont have any issues... the smog gods have crushed me.

I wonder now what the problem could possibly be.

I have a temporary permit so i will drive it like this until it passes smog.

Gamefreakgc

Sorry to hear that! A misadjusted TPS will sap power, so at least it runs well.

If you post the numbers, we can help direct you to what might be the cause. This is from the FSM, shows what component does what: http://personal.utulsa.edu/~nathan-b...72systempu.pdf. You can then look to see in what area(s) you didn't pass and then repair/replace components that could cause that issue.

If you were close... I know of a few tricks that will cause different NOx or HC readings... such as the temperature of your engine. I passed by 2 ppm on my HC on the last check! And adjusting the VAFM lean will cause lower HC's, but higher NOx readings, etc.

Gevo

Well, the numbers were slightly worse this time than the first time, and here are the first time numbers again.




Thanks for the FSM link, I will look at it and make sure to share it with the mechanic, although I seem to be trusting him thus far. Also, he hasn't charged me for the pre-tests (two of them) which is extremely nice of him.

Gamefreakgc

Yikes, that Carbon Monoxide reading is terrible! I would be afraid to ever have it idle in park... you'd gas yourself in a garage real quick...

Carbon Monoxide is formed when there's less oxygen available than needed for combustion. So instead of CO2 (harmless carbon dioxide), you get CO. Also, changing your fuel trims made your NOx go up, did you see? If you reduced the fuel trim down a few more clicks you'd get lower HC's (now at 98) but higher NOx reading, but you've got room to spare. Not sure why it's running that rich in the first place though!

The only system that might be affecting it would be the PAIR valve, nothing else would raise CO. But that reading is 10x higher than passing, there's got to be more going on than that.

Gevo

Gamefreak, you mentionedthat with a leaner engine the NOx goes up, and in fact it did... look at that, something happened as expected .

I'm gonna pull all the plugs and compare to see if they are evenly crappy or if one or more stands out.

I thought of another possibility... what if when my buddy rebuilt the engine harness he somehow crossed one or more of the injector wires, and now there are two or more injectors spraying fuel at the wrong times...? How would this manifest itself?

Sturmcrow

Gevo, I am pretty sure that all 6 injectors fire at the same time. I know it sounds crazy, but I read it a few months ago with some nice diagrams that show how it works and have not been able to find back that reference.

If you look at the wiring diagrams, however, there should only be one signal coming from the ECU to the 6 fuel injectors.

Sorry to hear about your continuing smog problems.

Gevo

Sturmcrow, I am retarded, because I literally wrote about my own surprise to how the fuel injectors work not to long ago on one of these threads. lol.

However, the way it's wired is two lines, 3 on each. SO, I guess this answers the question about the wiring to the injectors... blah...!

Punchy

The injectors do batch fire all six at once.
The wiring in order, Battery, Fuse AM2, IG2 (ignition switch), Injectors (Also Igniter and coil), From the injectors it splits into two lines ((1 3 5) & (2 4 6)) to the ECU.
But the ECU has both lines shorted (spliced) to each other on the finals inside so that both banks fire at once.

Gevo

I understand the words.. but can't wrap my head around it... Perhaps it's because of computing issues back in 1991? lol...

muddmadness

I sorry to hear you didn't pass smog Gevo, I had my fingers crossed all day for you

I have been following your progress and in a couple of posts you mention that you "dialed back the AFM a couple of clicks" are you talking about the air flow meter? How do you adjust it? Mine looks like a completely closed unit. Just trying to pay attention and learn, but I couldn't get the visual or wrap my head around how that is done.

Can I get the link for that video?

Gevo

Muddmadness, thanks for crossing your fingers.. lol..

Yes, Air Flow Meter can be adjusted although i suppose it's only meant to be done in the factory. On here and other forums I read that the stock configuration is pretty rich and it can be adjusted if you want. The following is a link of another forum that does a pretty good job at explaining what's happening.. Also has pics.

http://www.customtacos.com/forum/showthread.php?t=56229

This is a video that helps.

Advice from my experience, it's easy to do.. just make sure when you are cutting out the existing silicone you don't use to much force to go through the plastic cover and damage the interior. Also, have a high temperature waterproof sealant adhesive ready to seal the unit back. Also.. it was very cool to see it work

Gevo

So, punchy is right, the wiring diagram does splice the WHITE and WHITE-RED wires just before getting to the ECU. See wiring diagram here: http://snjschmidt.com/wiring/Engine_Control_3vze_2.jpg

SO! I will spend a few minutes to see if those two wires are correctly routed in the harness. I should be able to access one of the driver side injector connectors fairly easily...

Am I correct to say that the WHITE and WHITE-RED wires should NOT be shorting to vehicle chassis when the key is ON but engine OFF? It seems the BLACK-BROWN wire going to the other side of the injectors is the positive...?
I'm thinking there could be a ground short causing injectors to fire more.... I don't know, I'm thinking out loud.

muddmadness

Gevo, Thank you for the video, that's cool. But too lean is bad right? My old AFM had the silicone on it like it had been removed and I wondered if that was why it wouldn't run right but I was a little leery of messing with it.

PS: Good luck with the wiring harness, just finished mine but I'm still having an issue with engine surge when I press the clutch to shift, I have to tap the gas pedal to get it to drop down. Maybe it is supposed to but I think that it is still idling too high. I have to wonder if it isn't the timing or something.

Gevo

I wouldn't know where to begin to know where the right setting is for the AFM... Although I will be keeping an eye out on the spark plugs which should tell me if the engine is rich or lean.... this is AFTER everything is working properly and I pass smog.. lol.. just in case the 4 clicks lean on the afm is to much...

I hate the wiring harness... analog is good until you have too many components. lol.