rogh idle.....lack of power...then good...

Topic: rogh idle.....lack of power...then good... (Read 13270 times) previous topic - next topic

rogh idle.....lack of power...then good...

Reply #30 – May 13, 2015, 08:53:58 PM

I measured a 4 volt drop from my battery to my tail lights once. I even moved up to a better ground to make sure that wasn't the cause, and then ran another wire temporarily. With 2/3 the voltage, you will probably drop half the actual power (wattage) of the part.

I find most of the miss's I've fixed are either old spark plug wires or too high of an idle, generally caused by vacuum leaks. All those littleplastic hoses become very brittle and break where you can't see them. As soon as your idle is higher then the computer can control, it will start randomly cutting fuel and timing to try to bring it back down.

I highly doubt a modified engine uses more then 10% fuel at idle and low throttle and load situations. Most modifications actually make less power at lower rpm's vs a stock motor anyways and are quite a bit less efficient under the curve.

Part of the reason i like to pull codes first is because it might point you to a broken vacuum line, such as egr or map sensor, which might only be a problem under certain situations. Like part throttle, warm start cold start ect.

rogh idle.....lack of power...then good...

Reply #31 – May 13, 2015, 09:18:52 PM

Quote from: Haystack;448047

I measured a 4 volt drop from my battery to my tail lights once. I even moved up to a better ground to make sure that wasn't the cause, and then ran another wire temporarily. With 2/3 the voltage, you will probably drop half the actual power (wattage) of the part.

I find most of the miss's I've fixed are either old spark plug wires or too high of an idle, generally caused by vacuum leaks. All those littleplastic hoses become very brittle and break where you can't see them. As soon as your idle is higher then the computer can control, it will start randomly cutting fuel and timing to try to bring it back down.

I highly doubt a modified engine uses more then 10% fuel at idle and low throttle and load situations. Most modifications actually make less power at lower rpm's vs a stock motor anyways and are quite a bit less efficient under the curve.

Part of the reason i like to pull codes first is because it might point you to a broken vacuum line, such as egr or map sensor, which might only be a problem under certain situations. Like part throttle, warm start cold start ect.

At the tail lights, the wiring feeding them is also way undersized, and goes through too many circuits. One of the reasons I love the LED modifications in mine - above 8V, they are full output, and lower load.

Vacuum leaks, yes. Again, most people think they don't have any where in reality they may have a dozen various leaks. Small leaks add up. You can also have leaks on the lines going into the HVAC controls, which are a pain to do anything with.

The EEC has a stock tune. O2 sensors and adaptive learning are based on stoichiometric figures, nothing to do with AFR. The stock tune is setup for 14.7:1 AFR (stoich for ethanol-free gasoline), but stoich on E10 is 14.1:7, which is 9.6% more fuel required before the o2 sensor will begin to switch. This is where the 10% figure comes up. E10 will throw the EEC into the end of its adaptive learning range, without making a single change to anything else but fuel. Go just 0.5% more fuel needed, the EEC can't cope and adaptive learning fails.

Fooling the MAF sensor into saying you're pulling 10% more air in at any point in time would get the adaptive learning back into the middle of the range. In my car, my KAMRF is typically between 0.98-1.03 with my current tune - a 4-5% swing. If the tune is expecting E10, the same engine can only play with fuel enrichment in a KAMRF range of 0.898-0.904, 0.898 being maxed on enrichment and being unable to go further, causing conditions leaner than stoich when the EEC wants to see stoich.

Now technically you should be able to go leaner without anything but less cruise power and maybe some slight stumbling. Some people go to closer to 16:1-17:1 E0 fuel on the older Ford motors for extra fuel economy (Honda goes to ~22:1 on the wideband o2), but it will run in a way similar to what Vinnie is describing (works, but down on power and slight stumbles/misfires). Honda's 22:1 mode is good for a 40-50% fuel economy boost in their 1st generation insights. A couple mpg on the highway can be brought out in fox bodies and SN95 cars by leaning out the mixture a bit.

The 9.6% more fuel needed for max efficiency burn is also where most of the fuel economy drop comes from when using E10 vs ethanol-free. You simply need 10% more fuel to do reach the most efficient burn, and ethanol contains less energy. Because it jacks up the octane, you need to gain much of the energy loss back through timing. Much easier to do with knock sensors and the like...

Codes will help for obvious/more serious problems. A bad EGR valve can have a minor leak, but enough to cause a leaner condition. Again though, the o2s may see this lean condition and try to richen up, but be unable to go further due to E10 fuel and a stock tune. Adaptive learning is good at compensating for vacuum leaks, when it is allowed to work.

Here's what a stock tune looks like (Look at KAMRF - 10.2% enrichment):

And with a tune. 2.7% leaner needed on one bank which is well within normal range, but it means one bank is richer than the other, and it has been that way for many years - 2-3% adaptive leaning on bank 2 ( it is slighter richer than bank 1). Everything but my wiring harness has been changed since the original stock tune, including the engine block:

Just need to keep in mind that KAMRF = adaptive learning. 0.8984-1 means it is commanding more fuel than the tune, and 1-1.1211 means that it is needing to pull more fuel than the tune. KAMRF is adjusted based off of o2 readings (above of below stoich). Since E10 needs 9.6% more fuel to reach stoich, it will be running on the lower end of KAMRF, without any other causes of it needing to richen the mixture. Throw in differences in the intake , exhaust, coolant and air-charge temperatures,various conditions of sensors, solenoids, and hoses, aging of wiring, etc, that extra 1-1.5% of adaptive enrichening capability left in the tune means very little.

rogh idle.....lack of power...then good...

Reply #32 – May 13, 2015, 10:07:28 PM

Damm seek you been studying this stuff.. thanks for the lesson..

I'll send you my tune if your interested in seeing it when I finally get the software

rogh idle.....lack of power...then good...

Reply #33 – May 13, 2015, 11:43:25 PM

Quote from: Bob;448050

Damm seek you been studying this stuff.. thanks for the lesson..

I'll send you my tune if your interested in seeing it when I finally get the software

It's not bad if you simply ignore everything you think you know when going in. If you chase afrs, you will go crazy. If you tune for percentage from lambda (based on stoich), your tune will be good no matter the fuel type ( with minor tweaks to make it perfect). Our cars can't detect fuel type so we're stuck tuning for differences. A lambda value of 1 is stoich and 0.85 is good for wot, until you get up to something like E85 fuel. 85% of stoich is 12.5:1 AFR for gasoline and around 12:1 AFR for E10. E85 needs under 10:1 AFR! Lambda is pretty consistent though. KAM is simply adaptive changes to fhe base tune, in the same lambda-type percentages.

rogh idle.....lack of power...then good...

Reply #34 – May 14, 2015, 11:35:33 AM

This is off topic but I really need to get a Quarterhorse and a wide band so I can enter the MAF curve and injector slopes I want to run and be done with it. I doubt I'll pick up power but hey at least I can run a better MAF meter.

rogh idle.....lack of power...then good...

Reply #35 – May 14, 2015, 01:12:25 PM

Quote from: thunderjet302;448059

This is off topic but I really need to get a Quarterhorse and a wide band so I can enter the MAF curve and injector slopes I want to run and be done with it. I doubt I'll pick up power but hey at least I can run a better MAF meter.

But you can dial in your fuel much better, and mess with timing. Some people gain upwards of 50hp on motors with a lot of changes. I'd expect 10-20hp to be more realistic for most mild 302s. 50+hp tunes will only show up if you're running really lean at WOT (let's say lambda of 1). Most people would throw parts at such a car to fix those severe lean conditions though.

rogh idle.....lack of power...then good...

Reply #36 – June 08, 2015, 07:15:12 PM

Update.....so far so good. The car seems to be doing better. I replaced the throttle body and spacer gaskets, and replaced the injector harness. Apparently, my injector harness should have a ground wire that goes to the back of the head. The harness I removed did not have the ground wire. I'm thinking that may have been the issue, or part of the issue. I did that work yesterday morning. haven't had a lot of time lately. I also swapped my valve covers while I was at it.........shut up. LOL. So, I took off and the car nearly died and choked, I realized I have a near empty gas tank. LOL, SO more gas in the tank. But the car seems to be acting right for a change. I'll update again when I drive it a bit more.

rogh idle.....lack of power...then good...

Reply #37 – June 08, 2015, 07:41:20 PM

Old valve covers..whatcha gonna do with 'ems? :D

Good to hear..hopin' she acts much better for you. :)

rogh idle.....lack of power...then good...

Reply #38 – June 08, 2015, 07:54:12 PM

The old ones are my FPV covers. I'm going to restore them and stash them away. The new ones are different. I test fit the passenger side cover, and the baffle hit the rockers, so, I got the Dremmel, a cutoff wheel, and got busy. I cut the posts for the baffle screws in half, cut the baffle down the same amount, and all was well. I'm doing some visual mods to the upper intake and valve covers. The GT-40 upper is staying on the car. Now, to be honest, if I could find a dirt cheap Cobra upper, I would use that. I have some custom intake plates for it.......just no intake to put them on. I'll slowly start detailing now.

rogh idle.....lack of power...then good...

Reply #39 – June 09, 2015, 01:01:55 AM

I missed your post seek, lots of really good info there. Especially since we run e10 state wide here.

I recently moved to a county without emissions and one of the gas stations out here has ethanol free, I've been really, really tempted to fill up there since i learned about it last week. When we made the switch to e10 i noticed about a 7% drop in gas mileage and had a soggy bottom end. I actually ended up bumping my timing up to about 18* back in the day, and all of my other cars seemed to run much better and get most of the gas mileage back that way.

My 86 is really weird though, it runs like on anything but 10* but gas mileage seems to stay about the same no matter what its set at. When i couldn't get it through emissions a year and a half ago, it ended up that the timing was at 35* by the ballancer.

rogh idle.....lack of power...then good...

Reply #40 – June 19, 2015, 09:37:33 PM

The Bird seems to be running strong, idling fine (but lopey), had the a/c freshly charged up the other day, cold as can be. The replacement injector harness made a big difference with the orange ground wire. My harness didn't have a ground to it. One wire CAN make a difference. It wouldn't start today, I figured TFI and was correct. The MSD TFI ped out, so I took my last NOS Motorcraft TFI and installed it. All is good, and it's running better now than a few days ago, and I thought it was doing great a few days ago. LOL. One step at a time.

I gotta say, I found some issues out on my own, I found some issues out from you fellow members, I appreciate you guys.

rogh idle.....lack of power...then good...

Reply #41 – June 20, 2015, 04:25:11 PM

Thermal grease has gotten more efficient as PC CPU's have gotten faster and hotter. If you are not using the latest greatest stuff to mount your TFI, you may want to look into upgrading.

rogh idle.....lack of power...then good...

Reply #42 – June 20, 2015, 10:59:27 PM

what latest greatest stuff. Lay that info on me.

There's a remote TFI kit I can buy for about $50-$60 that could help a lot. Plug and play. I am sure thinking about that

rogh idle.....lack of power...then good...

Reply #43 – June 21, 2015, 09:02:25 AM

It's just dielectric grease to help the thermal transfer rate...in short, not axle grease. Smear a thin layer evenly, not too thick, not too thin, and bolt the TFI down. Do NOT, NOT, NOT put on a new TFI without....you'll have an issue shortly.

rogh idle.....lack of power...then good...

Reply #44 – June 21, 2015, 09:07:14 AM

I use that every time, I thought there was a newer, better product,