Injectors Vs Fuel Pressure

[BLG355]

Last night I ran another log, and I noticed before that something smells hot, not seeing it until last night, I have two mildly glowing manifolds. I know I have plenty of fuel now, so what could cause this? Do I need to modify something in the tune, maybe I have a bad O2 sensor? Everything looks fine on the log to the best I can tell. So I am going to get an emulator as well before I start burning chips, what do you guys recommend, and is there something in the tune I can modify that can give it more fuel(I am assuming it's lean) or is there something else I can look for with these glowing manifolds? The O2 sensor is a new one, it's a Bosch 3 wire. I was under the impression that the ECM will keep I from going lean based on the O2 sensor, is it still possible to go lean enough for the manfolds to glow? This was not ran hard, just a general drive around tow, fairly easily. any feedback is greatly appreciated. Thanks.


BLG

[Fast355]

Last night I ran another log, and I noticed before that something smells hot, not seeing it until last night, I have two mildly glowing manifolds. I know I have plenty of fuel now, so what could cause this? Do I need to modify something in the tune, maybe I have a bad O2 sensor? Everything looks fine on the log to the best I can tell. So I am going to get an emulator as well before I start burning chips, what do you guys recommend, and is there something in the tune I can modify that can give it more fuel(I am assuming it's lean) or is there something else I can look for with these glowing manifolds? The O2 sensor is a new one, it's a Bosch 3 wire. I was under the impression that the ECM will keep I from going lean based on the O2 sensor, is it still possible to go lean enough for the manfolds to glow? This was not ran hard, just a general drive around tow, fairly easily. any feedback is greatly appreciated. Thanks.

BLG

Check the ignition timing. The usual cause of glowing headers or manifolds is retarded timing.

[BLG355]

Check the ignition timing. The usual cause of glowing headers or manifolds is retarded timing.

I had the base timing as zero, but I will double check it and verify. Thanks.

[Roadknee]

The exhaust will be hottest when the A/F ratio is stoich (14.7 for gas). If run leaner combustion temps actually go down. Too rich of mixture with retarded timing will also cause high EGTs. Post a datalog when you get a chance.

[BLG355]

The exhaust will be hottest when the A/F ratio is stoich (14.7 for gas). If run leaner combustion temps actually go down. Too rich of mixture with retarded timing will also cause high EGTs. Post a datalog when you get a chance.

I didn't mess with the timing yet, but here is the log from last night. I was hoping the computer would keep it in check as long as I give it enough fuel(I am going to order chip burning stuff from moates this weekend). I'm not 100% sure what max timing should be on this...with most of my carb'd engines, an all of my race motors that didn't have fixed timing, I used to set the timing for overall and have it in by the stall speed of the converter...so this is new to me. I did run this chip with my base timing advanced 8 degrees without and problems. I was hoping with the tight quench and premium fuel to be able to take advantage of more timing. If I would get too much timing, the ECM would pull it back right?

This is 5.7 injectors with 25psi fuel pressure. Truck seems to run smooth, has a little shake at an idle. In open loop, it runs better with 25psi fuel pressure than 22psi...but when I start burning chips I guess I can fix that to give it more fuel in open loop. I may just advance base timing 10 degrees and see if they glow tonight.

BLG

[EagleMark]

Your timing in the starter chip is set to 26* WOT. So adding 10 to distributor is going to be a little to much. Just hang on and do it right when you get your equipment. You could be pushing it way to far on the decel end if you add 10*

When you do these logs start them when vehicle is totally warmed up, this is the data to use for adjustments. There's no use for engine warm up data in the main tuning end unless your looking for a warm up issue.

Also look for error codes before recording, like right now you have a Error 22 and 54 and I don't know if that will effect the data we are looking at.

The fueling VE is not bad but there are some areas that went rich, down to 109 just before it hits PE.

Saw one spot of WOT on there and since all we have is Narrow Band reading we'll look at that and it's in .928 range so we do have plenty of fuel but then the Injector Duty Cycle is climbing into 90s which is a little to high for me. But the NB was still reading plenty rich. This happens with TBI and they go Async fueling so the IDC is not always a good read.

At the end of log there was some idle data and it looked like IAC count of about 30 in drive and 15 in P, if you get them down just a little bit more it could help the idle quality... turn the throttle stop screw in 1/4 to 1/2 turn and check IAC counts again at end of next log. It's always good to leave a minute of Drive and a minute of Park at end of logs to check this. It's the only time the IAC counts should be used like this. Playing with idle timing when you get your tuning equipment is the other adjustment to smooth out idle.

[BLG355]

[QUOTE=EagleMark;40146]
Also look for error codes before recording, like right now you have a Error 22 and 54 and I don't know if that will effect the data we are looking at.
QUOTE]

Wow, I didn't think that would throw codes. DTC 22 is from when I was messing with the TPS to get the voltage back down near .54 from .70+ and DTC 54 is from when I changed plugs, I did a compression check to make sure I am getting some good psi, which cold it made 185psi, so I'm happy.

I feel like such a rookie lol. I was going to ask how did you know there was even codes...but them I went in and started looking around and sure enough I found it. Your help and patience is greatly appreciated.

I will double check the timing and also my timing lite. When I degree a cam, I always check the timing pointer to the mark in the balancer and then I scribe a line on the inner and outer rings on the balancer so if it shifts, I know about it. My light has an advance built into it, I have another that does not, I will double check it to make sure it is correct at zero.

I've been seeing that the NB isn't always accurate, but I was getting it richer each time I would up the fuel pressure, so I said what the heck and really jumped it up and finally got the readings over 900mv by going with 25psi. the idle also seems smoother like this, especially cold. Sometimes cold it would surge for 30 seconds or so, it seems now it doesn't is for 2-3 seconds and starts to smooth out.


Barry

[BLG355]

At the end of log there was some idle data and it looked like IAC count of about 30 in drive and 15 in P, if you get them down just a little bit more it could help the idle quality... turn the throttle stop screw in 1/4 to 1/2 turn and check IAC counts again at end of next log. It's always good to leave a minute of Drive and a minute of Park at end of logs to check this. It's the only time the IAC counts should be used like this. Playing with idle timing when you get your tuning equipment is the other adjustment to smooth out idle.

My timing lights read differently from each other, go figure. So I am trusting the one without advance built in, and I had slightly retarded timing, about 4 degrees. So I set it back to zero, which means I am either at zero or plus 4.

I turned the idle screw in 1/4 turn, I get 1 to zero counts, is this too low? should I back it out an eighth?

I noticed, when I was out playing with the truck, if I come to a stop sometimes the manifolds have a slight glow, sometimes not. When I get a glow, it seems like it does it after coasting or going own a hill for a while. I did a 1/8 mile run and stopped right afterwards and there was no glow, but cruising through town to my house, I coast down a slight grade until I pull into alley and then my driveway, they will be glowing and stop glowing after idling for maybe 20-25 seconds. It' not like they are bright red, I am looking at them in the total dark. if there are street lights or anything too close I can't barely even see it glow. I hope it's something I will be able to tune out of it.

Thanks again.

BLG

[brian617]

With the cleaned injectors and added fuel pressure you are very rich at cruise low load situations, probably the cause of bog and high EGTs glowing the manifolds? I'm no expert, just my take on your log Your truck sure does pull hard, makes me wish I'd modded mine more.

[Roadknee]

That does run really strong! My stock 1995 K1500 LO5 will pull 37 to 57 mph in second gear in just over 6 seconds. You're under 4. Wow!

I understand you're running base timing at 0 BTDC in this datalog. So your WOT timing is about 26 degrees. I think your combo could run 32-34 with your heads. Cruising at 2000 rpm and less than 50 MAP you're only running about 28 degrees total. I think your combo could use 40 or more. BLMs are rich in this area already and they'll become richer if you increase the timing so you'll need to reduce the VE tables too. These changes should reduce EGTs.

I think you could add 8-10 base timing for a quick test and go for a cruise to see how it impacts EGTs. Watch knock counts very closely if you're going to lean into the throttle.

[EagleMark]

I turned the idle screw in 1/4 turn, I get 1 to zero counts, is this too low? should I back it out an eighth?


Thanks again.

BLG

You could go out an 1/8th, but really your OK for now. Come middle of summer check it again after a good run, hovvering at 0-1 is perfect in park, you'll always get a few more in Drive.

With the cleaned injectors and added fuel pressure you are very rich at cruise low load situations, probably the cause of bog and high EGTs glowing the manifolds? I'm no expert, just my take on your log Your truck sure does pull hard, makes me wish I'd modded mine more.

As brain noticed it is very rich, right on the MAX allowed BLM low side at cruise low load situations, but it is more likely the extra amount of AE I added for the Vortec heads and was not looking for that much pressure... could also be a spark issue? Something is just not right with spark and even 2 timing lights are telling you something is not right? So it's set to 0* with bypass disconnected... or 4* what about bypass connected? Should be around 20* but it is going to be jumping around a little, just part of idle control of the PCM.

What 2 cylinders are glowing? Could there be a crossfire in those 2 spark plug wires? How do the plugs look on those 2 cylinders? Really sounds like a mechanical issue and not something that can be tuned out.