Surging RPM

How-to's and repair secrets for your 4WD can be found here. Have a question? Ask it in here!
User avatar
Petros
Highest Ranking Member
Posts: 11941
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Surging RPM

Post by Petros »

I agree with DLB, it does not sound like a problem in the carb. check your manifold bolts are tight, as well as the 4 nuts that hold on the carb. check the routing on all the vac lines (it only takes about 10 min despite the maze of hoses) and verify that none have leaks when you check their routing. Make sure the brake booster line is connected, the PCV is properly routed and the EGR vac lines are connected (or all capped off) properly.

After that you might go through each of the vac operated systems in the FSM and do the simple tests to verify they are working properly. None of the tests area difficult, you just have to systematically test/inspect each one in turn.

DO NOT randomly pull and plug the various systems thinking you might get lucky and find the problem, you must diagnose it first BEFORE you try and fix it. With a problem that severe it will be obvious what is causing it and how to fix it once you find the problem.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
T4WDOR
Member
Posts: 38
Joined: Sat Nov 05, 2011 7:24 pm
My tercel:: 1986 4wd 6sp 3ascv
Location: Southern Oregon

Re: Surging RPM

Post by T4WDOR »

Yup, I found the problem. Feel like a dummy haha. Woke up this morning to try to figure out the carb, traced all the vacuum lines and checked for wear(one had a tiny hole), then torqued the manifold bolts, which were all tight. Then started torquing the carb bolts, the first two were tight but on the third it just spun like crazy, and i figured the ratchet wasn't on, but it turns out my buddy and i were so preoccupied with that fourth bolt that we only finger tightened that one!
I guess we were too anxious to get it running. Anyway, i now have a good running 86 with a japanese 3a-scv engine! Which means i'm selling my daily driver to fund my trip to asia. Ill post it tomorrow, for someone in the club to buy. I have a thread in the gallery, her name is Topanga.
User avatar
marlinh
Highest Ranking Member
Posts: 1586
Joined: Sun Apr 08, 2012 9:15 am
My tercel:: 'Everett' Blue 87 4WD Wagon (Rocky 86, recently retired)
Location: Kootenays

Re: Surging RPM

Post by marlinh »

Just looked at your pics. What will you be asking for your car? May be interested...
T4WDOR
Member
Posts: 38
Joined: Sat Nov 05, 2011 7:24 pm
My tercel:: 1986 4wd 6sp 3ascv
Location: Southern Oregon

Re: Surging RPM

Post by T4WDOR »

Post Reply