Deceleraion issue 1800-2000 RPM's...TURTCEL

[TURTCEL]

So, I can't quite figure out what is going on but I will describe my issue the best I can and see if I can get any advice on what to check.

While driving, especially in 3rd gear (most noticable) when the car is going around 30mph and I let of the accelerator and the RPM's drop from 2000 to 1800 RPM's (approx) I get a very slight stutter. Not really bad but noticable. i have driven 2 other Tercs recently and neither have this issue.

I have completely blocked off the EGR system and removed it. My timing is set to 10 degrees BTDC. I can not find any vacuum leaks anywhere. The dizzy is a parts store reman. The carb is a Guarantee Carbs rebuilt. Complete tune up with filters. Tons of other stuff.

My thought was by the way it feels is that the vacuum advance port for timing retard might not be working. Seems like the advance is not completely backing off. Does this sound like a feasable thought?

What other components are active during these conditions that could cause this symptom? The car runs great at all other times but can't figure out why she is acting up at this point during driving.

The condition is actually still there in other gears but just doesn't seem as bad. Definitely not drivetrain related.

Peace

[dlb]

My thought was by the way it feels is that the vacuum advance port for timing retard might not be working. Seems like the advance is not completely backing off. Does this sound like a feasable thought?

there is no vacuum retard. the lower port on the vac advance unit advances timing at highway cruising, the upper port without the brass restriction advances timing at idle and highway cruising, and the upper one with the brass restriction advances timing even further at high altitudes.

i hate to say it but it sounds like a vac leak. maybe a fuel cut solenoid, judging by when it happens.

[Petros]

the problem is in the carb/fuel system most likely, check the FSM to see what system activate at those rpms and than test those systems. the solenoid is good guess, could also be the mixture control.

Malfunction in the vac advance will not cause anything like that unless it is acting like a big vac leak.

[TURTCEL]

Thank you so much for the advice guys. Figured when I got home tonight that I would have heard from you two. I will check those parts tomorrow. I have an '87 parts rig that I am in the middle of dismatling so I should have test parts as long as they are ok on the '87.

I thought it could be a vacuum leak but I was also wondering about the fuel solenoids...only because I now nothing about them but looks like I soon will.

I will keep you posted on what I find. I believe these componets are in the fuel and emission sections of the FSM correct?

Peace

[ARCHINSTL]

This is a long thread (65 posts!), but you may find something of value here: https://tercel4wd.com/forums/viewtopic.php?f=4&t=1372
Tom M.

[TURTCEL]

Thanks Tom, 65 posts is nothing when it comes to learning about my Terc. Can't even count how many I have read since I started looking at this website...long before becoming a Terc owner. Every bit of info that I get just helps make me understand this Yota system more and more.

Thanks again for all the leads guys.

Peace

[TURTCEL]

So I did some work on TURTCEL today to see what the issue was with the stuttering. I found that when I disconnected solenoid A on the fender well the car would not have the deceleration issue. So I swapped it with my '87 parts rigs solenoid and it is better but still slightly there. If I disconnect solenoid A and plug the line and just leave it that way will I cause any damag =e to my engine or other components? It seems to run really goot when it is plugged off.

I have replaced all the vacuum lines on the car twice now in the last 2 months thinking that they were a little big for the lines they fit on. I believe that I am having very small vacuum leaks all over the place because of this. I am headed to the parts store again to grab just a little smaller hose and will replace everything to make sure all are really snug fits.

I will report back later.

Peace

[TURTCEL]

So I repaced all my vacuum lines again (for the 3rd time) with 2.8mm hose compared to the 4mm hose that I had on the car. It fits really snug and I for sure have no vacuum leaks at any hose connections now.

Te car actually feels like it accelerates better now but tomorrow I will have to recheck my timing and carb settings since I am sure there were a few very small connection leaks that prob added up to a considerable leak. Car has a litte pop in the exhaust now at idle so I think I need to adjust my mixture a litte too.

Still not sure if the stutter is gone but it seems to be for now. The vacuum leaks on these cars can cause such a headache.

Peace