[455'73inElCamino]

How do I tell if I have an exhaust leak?

I have read the spark plugs and they look like I would expect them too. I do not see carbon on the plugs as if it is running rich.

Carl

[JLMounce]

You can use some soapy water sprayed on to areas where there could possibly be leaks. Around header gaskets, where pipes merge or are bolted together, at the o2 bung. Start the car and spray lots of soapy water on those areas, look for consistent bubbles in the same place. This is somewhat difficult and becomes more so as the exhaust gets hotter however.

One real way to do it is to look for soot marks on gaskets, pipes etc. that would indicate exhaust gasses are leaking.

The final thought on the oxygen sensor is it's general placement as well. You want a minimum of 18" past the o2 sensor before pipe exit to cut down on possible false reading from reversion.

If your plugs look good though, it's possible you have a thirsty engine. Are your e-heads the old bathtub chamber heads or the newer version with modern chambers?

[HWYSTR455]

Start a new thread. You can post progress, metrics, problems, and it's specific to your case.

Here's a thought. What's your time curve look like? It may just want way more advance. Maybe post full specs of your setup and you may get a little more focused responses. When running EFI, even low RPM number are higher and seem adverse than when running a carb. As an example, idle advance is usually in the 16-18 range, and can be as high as 22-24.

There's a number of factors on determining, and anyone making suggestions on a timing curve. It can vary 10-15 degrees, and rate can vary by 1500-2500 RPM.

.

[455'73inElCamino]

Originally Posted by JLMounce

One real way to do it is to look for soot marks on gaskets, pipes etc. that would indicate exhaust gasses are leaking.

The final thought on the oxygen sensor is it's general placement as well. You want a minimum of 18" past the o2 sensor before pipe exit to cut down on possible false reading from reversion.

If your plugs look good though, it's possible you have a thirsty engine. Are your e-heads the old bathtub chamber heads or the newer version with modern chambers?

Unless my builder pulled a fast one, the heads should be no more than 2 years old so should have the modern chambers (d-port heads).

I will start by looking for soot marks and at the O2 placement. Are you saying that the O2 has to be 18" away the collector flange? In my case I think the collector is 18" but I will check. If this is the case then the O2 can't be that far away. If that is the case, then can I assume that transitioning to a 3" pipe at the collector output will resolve a possible reversion issue, at least as much as possible?

[HWYSTR455]

Hm. I dunno, I've run the collectors with the O2 bungs in them a bunch of times. Should be fine.

SD CNC chambers on 72cc E-heads you say? Think they can take like 40-42 total advance with vacuum at light throttle, in the 18-2400 range, know where you're at now, and what's your SCR? Thermostat you're running?

Ever heard it ping?

.

[TedRamAirII]

Use a Yard Blower or a air hose from your compressor and Duct Tape the hose to the tail pipe so you you get some pressure. Now take soapy solution, (I like Whitewall Cleaner) and spray suds at all joints and the O2 bung. A leak will surely make the reading go wonky!

[Squidward]

I have my O2 sensor no more than 6" from my collector flange, maybe closer to 4". The collectors are short on my 1st gen Heddman's. Where in the header would reversion occur such that it would adversely impact sensed AFR? Fitech instructions pretty much said farther back on collector is good, don't put it on the bend of a single tube, and don't put it too close to the exhaust port outlet.

My stuff runs nicely, but I'm just trying to digest some theory here.

[JLMounce]

Originally Posted by 455'73inElCamino

Unless my builder pulled a fast one, the heads should be no more than 2 years old so should have the modern chambers (d-port heads).

I will start by looking for soot marks and at the O2 placement. Are you saying that the O2 has to be 18" away the collector flange? In my case I think the collector is 18" but I will check. If this is the case then the O2 can't be that far away. If that is the case, then can I assume that transitioning to a 3" pipe at the collector output will resolve a possible reversion issue, at least as much as possible?

The o2 sensor can be in the collector flange. You want 18" of pipe after the o2 sensor before the pipe exits to atmosphere. As long as you're running a full exhaust system, that's more than likely how you have it setup.

[64speed]

Any updates on driveability?

[455'73inElCamino]

I am hoping to get everything finalized this week on my install.

I am having a heck of a time getting the full filler neck to tank tubing put on.

Throttle body wiring I am finalizing.

Fuel pump, I am running new power wire and ground since the amperage is higher than my prior fuel pump.

I changed my mind on liking the fuel line "in" location being on the back (firewall) end of the sniper. I have a bracket on the back that supports the TV cable for my 2004r Transmission, brake booster vacuum hose, and of course the distributor. There is just a lot of stuff there. Sure, it make make things look cleaner by minimizing the view of the fuel lines, but it just don't like the idea of fuel lines in the area of high voltage.

[Interceptor]

Originally Posted by 64speed

Any updates on driveability?

Driveability is great, it's pretty much what you make it. Funny thing about being able to set your AFR anywhere you want is ... you don't really know where you want it. I've been toying with the AFR (you can easily set basic parameters for idle, cruise, and WOT, cell-by-cell values are adjustable as well) to get rid of the exhaust odor, run smoothest and get best economy and I think I'm doing OK, but there are probably times when it could benefit from a dyno tune with a knowledgeable tech.

Generally I've been setting Cruise AFR leaner and leaner until I feel surging on the freeway, then back off. Currently 16.0:1, any leaner and it stumbles on accel transition. Idle AFR, leaner until it idles rough, currently 14.5:1. Runs really smooth at 13:1 but smells like raw fuel. Haven't messed with WOT as it seems to run fine there at the baseline (12.5:1.)

Plugs are light tan. Engine actually doesn't so far run noticeably better than the QJ I had but doesn't smoke at idle, starts perfectly etc. Maybe a little crisper off-idle acceleration due to being generally leaner. I'm sure my QJ was leaving some on the table but I got tired of trying various experts that didn't really know how to tune it, and I have no interest in becoming a Carb Guy.

[455'73inElCamino]

I feel the same way about a carburetor. While I was able to resolve most of my tuning issues, there were some compromises that I needed to make with the carburetor that I did not like. Primarily these compromises relate to a carb only being able to respond to vacuum. Fuel injection can take into account other parameters that a carb can't.

Further, lets face it, none of us are getting any younger, and fewer and fewer people are able to tune a carburetor. So fuel injection seems like a reasonable solution.

Hopefully things go well with my install as it has on yours.

[455'73inElCamino]

I just realized a problem that I didn't notice before.

the sniper throttle linkage is setup to use a throttle "stud". My car 1966 uses a rod to connect from the pedal lever to the throttle in has a "hook" on the end of it and no obvious way to connect to a "stud".

How do I solve this problem??

On the quadrajet, I only had to slightly enlarge the hole on the throttle linkage to accept the nylon pieces that slides onto the throttle rod and allows smooth operation. The Sniper doesn't have enough material to do the same modification.

[HWYSTR455]

Convert to a Lokar cable and bracket.

.

[HWYSTR455]

Keep in mind that plug readings will change, as will AFR, if you change the timing table. Make small changes to timing, then go back to AFR, and back & forth until you find the best all-around results.

Weather effects it too, and it's better to go towards the safe side, especially for those times you are outside of your usual driving conditions.

.

[JLMounce]

Originally Posted by HWYSTR455

Keep in mind that plug readings will change, as will AFR, if you change the timing table. Make small changes to timing, then go back to AFR, and back & forth until you find the best all-around results.

Weather effects it too, and it's better to go towards the safe side, especially for those times you are outside of your usual driving conditions.

.

Yup, this, don't make wild changes all at once. Determine any issue you're having and sneak up on it in small tuning increments. If you're having the unit run your timing, or your changing timing yourself, you may need to make fueling changes as well.

As far as weather is concerned, you really shouldn't have to worry too much about this if you basic map that you've built is where it needs to be. The system will adjust to changing weather and altitude as recorded by it's map sensor, cylinder temperature and coolant temp.

If you are making very large, rapid changes in altitude and weather (for instance heading from norther AZ to the valley in the spring) you may need to make some manual adjustments, but otherwise, I've found that these systems are pretty good at keeping you where you need to be with typical seasonal changes.

[455'73inElCamino]

Originally Posted by HWYSTR455

Keep in mind that plug readings will change, as will AFR, if you change the timing table. Make small changes to timing, then go back to AFR, and back & forth until you find the best all-around results.

Weather effects it too, and it's better to go towards the safe side, especially for those times you are outside of your usual driving conditions.

.

I have learned what you have stated in tuning my quadrajet with my "new" higher compression higher performance engine with the 2004R. I have had to tune for "worst case" which is being in overdrive when going up hill on a hot day at moderate throttle.

Optimizing (really compromising) for this condition has lead me to an idle condition that I do not like. For this situation, more fuel at the overdrive/heat/load situation is needed to prevent pinging but this increased APT spring forces me to raise my idle speed to generate enough vacuum so that the APT spring is not "active" so that I don't have excess fuel at idle. I don't like that and have no plans to go to a looser converter to tolerate the higher idle.

If I understand what can be done with this efi system, I should be able to address the above situation, and add timing control if I ever have enough time to do that.

As you have mentioned, I have also seen the changes in other weather as well.

[JLMounce]

Originally Posted by 455'73inElCamino

I have learned what you have stated in tuning my quadrajet with my "new" higher compression higher performance engine with the 2004R. I have had to tune for "worst case" which is being in overdrive when going up hill on a hot day at moderate throttle.

Optimizing (really compromising) for this condition has lead me to an idle condition that I do not like. For this situation, more fuel at the overdrive/heat/load situation is needed to prevent pinging but this increased APT spring forces me to raise my idle speed to generate enough vacuum so that the APT spring is not "active" so that I don't have excess fuel at idle. I don't like that and have no plans to go to a looser converter to tolerate the higher idle.

If I understand what can be done with this efi system, I should be able to address the above situation, and add timing control if I ever have enough time to do that.

As you have mentioned, I have also seen the changes in other weather as well.

Yup, these self contained TBI style EFI's will certainly help you with that. I can only speak directly for the FiTech since that's what I use, but especially with timing control, you have the ability to tune for cruise/idle part throttle and WOT situations from idle/off idle through your rpm range.

That means you can tune for your worst case scenario, while not effecting your idle or WOT operation.

[455'73inElCamino]

Originally Posted by HWYSTR455

Convert to a Lokar cable and bracket.

.

Looks like I cant do this with a cable and bracket change only. I would need to change the gas pedal as well.

Not thrilled about this.

[Scott65]

I'm enjoying reading about everyone's adventures with efi. Being able to infinitely control timing, even if what I want is a non linear curve, is what motivated me to take the plunge.