Rough running

[grad70]

So I have been able to get my 6L 70 C10 to start, however it seems to idle about right but when I give it throttle it doesn't like it at all. It really sputters and runs awfully rich. Currently only have open Doug thorely headers with the 02 bungs. Does running open headers throw off the oxygen reading that much?

I have a feeling my MAF sensor is junk but haven't had time to dig into this much as I have been traveling a lot lately. I plan to pull ltft to see if there are any other issues I can troubleshoot.

New rear mounted gas tank, fuel filter, spark plugs, and I have recently had all the injectors out. I cleaned them with a syringe and a 9 volt battery.

Any opinions are appreciated. Thanks!

[solidaxel]

How are you going to test your MAF?

[BR3W CITY]

Disconnect the MAF and see if it improves. Having open headers WILL throw off the 02s by a good amount. You want at least a foot of pipe after the 02's to prevent clean air being accidentally monitored and dumping rich.

What are the AFR's looking like when it sputters/goes rich like you described?

[grad70]

Yes, I planned on just disconnect the MAF and seeing if it helped, or I might possibly be able to get my hands on another one to temporary install before going out and buying one.

I have the collector for the headers I can bolt on to add some extra "exhaust" pipe length to see if that helps. I have only a couple of days this week back in town so I doubt I can get it in for exhaust in that short of time. I'm thinking of going with some magnaflows and dumping right before or after the axle. Plan on having an X or H pipe setup.

[grad70]

I just got my exhaust system installed..... The truck sounds to be running better than before the exhaust was put on and with the MAF plugged in. However, before the exhaust was installed the LTFT was maxed at the positive 25% and now with the exhaust it took a 180 turn to the -25%. Any ideas what might be going on here? This is for both Banks 1 & 2.

Additional information is that the LTFT tries to go back towards 0 when I give it some throttle. Also the O2 sensors on both banks do not oscillate, they tend to stay high (close to 1). They only drop close to zero when rpms are increased...

[grad70]

I never did disconnect the battery after having the exhaust installed. Should I do this and let the computer have a fresh start?

[grad70]

So, latest update was that I contacted speartech about the situation. They admitted that the tune was not correct for the engine swap that I have. They requested it be sent to them and they would update the tune at no charge. I should get the computer back again sometime this week. Looking forward to seeing how much this helps.

[CarterD2015]

Thx for the update. Let us know if the tune helps.

[Hart_Rod]

Originally Posted by grad70

So, latest update was that I contacted speartech about the situation. They admitted that the tune was not correct for the engine swap that I have. They requested it be sent to them and they would update the tune at no charge. I should get the computer back again sometime this week. Looking forward to seeing how much this helps.

I would also change your spark plugs because they probably fouled due to the improper tune. Also, for future reference, always get the exhaust finished prior to trying to run the motor or mess with the tune. You will save yourself a lot of headaches.....ask me how I know.......

[grad70]

Originally Posted by Hart_Rod

I would also change your spark plugs because they probably fouled due to the improper tune. Also, for future reference, always get the exhaust finished prior to trying to run the motor or mess with the tune. You will save yourself a lot of headaches.....ask me how I know.......

I just installed new spark plugs in the engine and only ran it for less than 30-45 minutes with the bad tune. I think they will be okay, but still might keep that in mind.

Thanks for the opinion.... It's so hard to wait for exhaust when you want to make sure it starts (First LS swap). Yes, the exhaust really changed the scans that I did on the engine. The best thing is I had no intention or ability to adjust the tune before exhaust. I purchased hptuner after the exhaust was installed.

ECM & TCM are scheduled to arrive Thursday!!

[BR3W CITY]

With a bad enough tune, you can kill a sparkplug in one pass/dyno pull. If your not using copper plugs, switch now (and ignore the people who tell you about what the manual says, it does not pertain to performance vehicles). They are cheap, predictable, gapable, and you can access a a list of + or - heat ranges if needed.

If your planning on working on your own tune, this is going to be even more important. You can chase problems for days because you were confident something wasn't the problem. Reading plugs is still beneficial even on these things.

Oh, and get a wideband or self tuning will become really, really, really frustrating.

[grad70]

Originally Posted by BR3W CITY

With a bad enough tune, you can kill a sparkplug in one pass/dyno pull. If your not using copper plugs, switch now (and ignore the people who tell you about what the manual says, it does not pertain to performance vehicles). They are cheap, predictable, gapable, and you can access a a list of + or - heat ranges if needed.

If your planning on working on your own tune, this is going to be even more important. You can chase problems for days because you were confident something wasn't the problem. Reading plugs is still beneficial even on these things.

Oh, and get a wideband or self tuning will become really, really, really frustrating.

Thanks for the input.

Wideband will be the early xmas present to myself. I really wanted the scanner so I could log the idle, 1500, etc data during the first several times of startup. Wideband will come in handy as more mods come into play (very slow process).

[grad70]

Just got the fresh tune on the E38 last night. I had enough time to get my computers connected and HPtuners kickin last night for a quick data logging session sitting in the garage. The best thing is that my fuel trims look 100 times better than before. I hope to get time to take the truck out for a little cruise to see how the numbers look with some rpm changes and some time for the ecm to "learn".

[grad70]

I took it out for a spin yesterday and reviewed the logs. She is a lot better but we still have -8-10 for LTFT's both banks. I will be looking through the tune to see if there is anything significant that sticks out to me.

[BR3W CITY]

Your pulling fuel. When you log, try and load all the cells from 50-95kpa (you won't usually get perfect vacuum), and get a few counts on each cell.

Watch that vs the AFR error (not just afr). You probably have your VE set a little too high. Go back and see that the Fuel table doesn't have an anomaly.

If you using a non-stock injector, verify that you calculated the differential for injector @ rail pressure.

[grad70]

Thanks, I will look into that. Right now I don't have any time after work as I head straight to the field for harvest.

As mentioned before I have yet to buy a wideband sensor, any recommendations? If you keep it with the vehicle and run a gauge, where have you mounted it?

[BR3W CITY]

I've used Autometer, Innovate, and a few others, and most have been good. Do you have HP Pro (which has the box interface for the wideband logging direct?)

Most Widebands only use 1 of 3 common sensors, and your largely paying for the gauge or the interface and any other "value added features. I really like the Autometers, provided you get the ones with better Bosch sensors.
Be wary of "off brand" sensors, they have a short life and lack repeatability.

Innovate tends to be the best if you plan on using it to tune many different vehicles. Its the most calibrate-able and has the highest accuracy in general.

The Autometers with the good sensors are very comparable, but the gauges/displays tend to have a slower refresh/polling rate. This means that the real time display can be a few ms behind...harmless in overall usage, but important to know when pushing the envelope.

There is also a very cool way of ditching the stock 02's entirely, replacing them with dual widebands, and using wideband input to HPT for trims. Thats the most expensive, most complicated way (so its kinda cool )

[Aruba1]

Mine did something similar. I cleaned the MAF and it improved somewhat. Next I replaced the Throttle Positioning Sensor and the truck runs good finally. Google TPS LS1 for the symptoms.

[grad70]

Originally Posted by Aruba1

Mine did something similar. I cleaned the MAF and it improved somewhat. Next I replaced the Throttle Positioning Sensor and the truck runs good finally. Google TPS LS1 for the symptoms.

Good call. Already cleaned the MAF. I did notice that the position sensor was off when i was logging my data. I will reset it when I am back by the truck again.

[grad70]

Originally Posted by BR3W CITY

I've used Autometer, Innovate, and a few others, and most have been good. Do you have HP Pro (which has the box interface for the wideband logging direct?)

Most Widebands only use 1 of 3 common sensors, and your largely paying for the gauge or the interface and any other "value added features. I really like the Autometers, provided you get the ones with better Bosch sensors.
Be wary of "off brand" sensors, they have a short life and lack repeatability.

Innovate tends to be the best if you plan on using it to tune many different vehicles. Its the most calibrate-able and has the highest accuracy in general.

The Autometers with the good sensors are very comparable, but the gauges/displays tend to have a slower refresh/polling rate. This means that the real time display can be a few ms behind...harmless in overall usage, but important to know when pushing the envelope.

There is also a very cool way of ditching the stock 02's entirely, replacing them with dual widebands, and using wideband input to HPT for trims. Thats the most expensive, most complicated way (so its kinda cool )

Yes, I have HP pro!
I have never had a wideband before and there seem to be several out there to choose from. I would like to buy one that I will not regret. I wouldn't be opposed to having a gauge in the c10 but i dont want it just anywhere. I want it to look clean, as if it might have came with one from the factory (even though my c10 is probably the roughest looking truck on this site, i still want the gauge cluster clean). Does anyone have a pic of how they mounted their AFR gauge. I think i saw something from dakota digital mentioning capabilites of showing this. I would be interested to see how/where they incorporate the gauge in the cluster.