Exhaust gas analyzer

I'm trying to dial in the carbs on my 78 308. I started looking at gas analyzers but it seems so many of them have OBD2 connections and all sorts of other stuff that wont help me a bit.

Anyone have a suggestion for a fairly simplified version at a reasonable price?

 

I had been looking at them. Was able to find the "basic" kit which still has more stuff than I'll need (which was a bit cheaper) on Amazon. Should be here next week. That'll give me time to do somemore carb work. Going to check float heights tonight.

 

I bought the basic kit from innovate. Picked it up on amazon for $250... Innovate Motorsports 3837 LM-2 (BASIC) Digital Air/Fuel Ratio Wideband Meter (1 O2 Sensor):Amazon:Automotive

 

I had been looking at them. Was able to find the "basic" kit which still has more stuff than I'll need (which was a bit cheaper) on Amazon. Should be here next week. That'll give me time to do somemore carb work. Going to check float heights tonight.

 

Well I got the unit today but didn't think about power for it. My older 308 has the small euro cigar lighter so I had to order an adapter. Now I get to wait for it to arrive. Gonna get this all set up on the computer though so when the power cord gets here I can plug and go....I hope!!

 

The plugs are there but I don't think I want to try getting them out. I got the clamp for the exhuast with it.

Now I'm having issues getting the stupid thing to idle. It seems like I have a vacuum leak but I'll be darned if I can find it. I set the carbs all back to base settings. Once I get the idle set around 900 any touch of the throttle and it either dies or starts to take off.

I thought maybe the linkage ball joints were binding so I cleaned and greased them.

Checked the timing again when I had a decent idle and it was good.

I'm about to the point of giving up and towing it to my mechanic and begging for mercy.

 

I was going to say I don't want to hijack this thread but it's my thread so here goes!

Just to set the whole stage, I installed pertronix in one distributor and had both distributors rebuilt. I had the car running and ended up with some other issues and have spent a long time working through them (starter, throttle cable, fuel pump and hoses...).

I went back to the beginning with the distributor install last night just to make sure I had everything set properly. I also installed new plugs and wires when I did that work. Went back through all of that too even continuity checks on the wires. I'm confident it's all set properly.

So...I had everything idling pretty decent a week or two ago and synched the carbs per Birdman's tutorial. I had everything dialed in pretty well at almost exactly 450 at ~900rpm. But I had a big lag between the front and rear banks because one of the turnbuckle links seemed loose. I also had the same issue with taking off once I touched the throttle. That's when I took the linkage apart, cleaned and greased and reinstalled. Boy are those tiny cotter pins a pain!! I made sure I didn't tighten the end caps too tight also.

Now when I get it to idle it's up around 600-700 at ~900rpm. I wanted to set the idle back up at 1500 and go through the sync again but I ran into the problems again.

When I had the idle set decent, timing was at ~6°btdc. I'm running BP6ES plugs gapped at .029. I'm running NON ethanol gas and my current jet set-up is 60 idles, 135 mains, 170a/c with f36 et's. I went to the 60 idles because even when I had it idling decent a couple weeks back there was a huge stumble off idle. Yes I did the synch with the idles stops backed out.

Steve your "not all cylinders contributing at idle" seems like a very likely culprit, but what would cause that and what would cure it? That seems to make a lot of sense too because adjusting the f/a screws on a couple barrels doesn't seem to affect idle much.

Appreciate the help gents! I consider myself pretty smart and a decent home mechanic but this thing has got me amazingly frustrated. It seems like I make headway and am close to getting it dialed in and it all goes to hell again for no apparent reason.

 

My bad, got carried away with the zeros. Should have been 4.5kg/h and 6-7kg/h per barrel using a standard airflow synchrometer.

 

I'll try that. I'm not sure as far as the mixture screws, but last time I played with them I set everything to 3 turns out and went from there. There were a couple barrels that were popping and took about another turn or two at most to stop the popping.

I planned to start over with the synch process once I got it to idle decent. Just never made that point yesterday.

 

Alright I'm about baffled here. I tried some other things like swapping wires from the Pertronix units (didn't figure it was likely since I did have the car running at least), I went back and checked the install of the distributors again, played around with the power and tach wire just to see if that made any difference, and who knows what else.

I still get the same issue. The car seems to idle fine and then just seems to take off for no apparent reason. Today I had it idling at about 900 and was walking away from the car to grab a wrench and it just idled right up to about 1400-1500.

During the few minutes it was idling decently I tweaked the linkages and got the carbs very close to even, but airflow was up around between 6kg/hr and 7kg/hr.

I'm going to try swapping the wires and caps out for the old ones just to see if it's something there. Other than that I'm thinking it has to be a carb issue but why would it suddenly be getting more gas or air without touching the throttle.

Any idea would be appreciate. I didn't get around to checking each cylinder to see if they were all firing at idle so will see if I can get that done too. It also seems to my ear like the tach is reading low but if I try slowing the idle down any more the car ends up stalling. I have a little inductive tach you slide over the cable, but it jumps around and won't give me an accurate reading.

 

Before I took anything off I went back and re-checked the timing. It's jumping around and the idle won't stay steady long enough but when it's right at about 900 the timing is pretty close to 6° btdc.

I'm going to go ahead and swap the wires and caps and probably plugs at the same time and see what happens.

 

I worried about that as well. I did a quick test fit with the clamp and wondered if it would hold without leaving a permanent mark on the exhaust tip. We'll see what happens, I have some work before I'm ready to use the LM-1.

I bought new plugs and have new wires. I'm going to try those two things tomorrow and see what I come up with!!

 

Well hopefully I made some progress. I swapped the plugs, wires, and caps and it didn't seem to make a whole lot of difference. Was still having most of the same issues. I left it sit for awhile, have been busy with other stuff anyway.

I got back at it today and first wanted to re-check the timing. I think I had it advanced too much. The marks on my flywheel are hard if not impossible to read which really had me vexed when I was setting the whole thing up initially. I retarded the timing back to the PM marks versus what should be +6° and the idle smoothed out. I tweaked the carb synch a bit more and it seems to be running decent at the moment. I've still got some parts and pieces (including the airbox) off so didn't take it out for a drive, but at least revving it in place it seems to do ok now. Slides back down to idle pretty evenly.

There seems to be a bit of a stumble just off idle but I should be able to even out little problems like that when I start playing with the A/F meter. I want to see if I can get things somewhat buttoned up tomorrow and take it for a drive and see what happens.

The only thing I can figure is with the timing too advanced maybe the advance was right on the edge of kicking in and that's why it would all of a sudden run up. Oh, and after tweaking the carbs a bit more they are all sitting at between 3.5-4 at 900rpm. Much better.