| Author |
Message |
Dave328GTB (Hardtop)
New member
Username: Hardtop
Post Number: 40
Registered: 1-2002
| | Posted on Sunday, March 17, 2002 - 11:21 am: | |
Jerry,
Checking grounds is a good idea. I would also have close look at the fuse box for signs of failure, poor connections, melting, etc. This is a weak point on 308's.
Dave |
Jerry H (Jerry)
Junior Member
Username: Jerry
Post Number: 98
Registered: 3-2001
| | Posted on Sunday, March 17, 2002 - 8:29 am: | |
Update... I am unsure if this problem is the tach itself. All the instruments around the tach are also effected. It seems to appear when the engine is warmed up. When I am at idle and I have the hand brake on I can see the brake indicator light on the tach glow brighter when the tach is reading right and dim when the reading is low. I watched this cycle like this for several minutes. Everytime the light got dim all the instruments in the cluster would drop there readings. This to me sounds like a grounding problem. Any ideas or experience with this???HELP. |
magoo (Magoo)
Intermediate Member
Username: Magoo
Post Number: 2134
Registered: 2-2001
| | Posted on Thursday, March 14, 2002 - 10:51 pm: | |
Greg, You might want to check it at 90mph. You probably will find you are doing somewhere closer to 80 mph.. Just a thought. |
Greg Owens (Owens84qv)
Junior Member
Username: Owens84qv
Post Number: 234
Registered: 10-2001
| | Posted on Thursday, March 14, 2002 - 8:19 pm: | |
Yes, my tach reads 500prm and my speedo reads 10mph parked. As long as it reads correctly when I'm doing 90+, I don't care!
There have been other posts / threads on this tach / speedo topic. |
Richelson (Richelson)
Member
Username: Richelson
Post Number: 599
Registered: 12-2001
| | Posted on Thursday, March 14, 2002 - 8:52 am: | |
Isn't it true that most 308 tachs and speedos read slightly high? |
'75 308 GT4 (Peter)
Intermediate Member
Username: Peter
Post Number: 1680
Registered: 12-2000
| | Posted on Thursday, March 14, 2002 - 12:28 am: | |
Yes, Bret, there is the edit button in the top, right-hand corner of the post field (the little paper and pencil) |
Peter S�derlund /328 GTB -88 (Corsa)
Junior Member
Username: Corsa
Post Number: 122
Registered: 4-2001
| | Posted on Wednesday, March 13, 2002 - 11:55 pm: | |
It's a common problem that the tacho show the wrong value on 328s. My needed to be calibrated. In some cases you need to change some parts in it. It's not expensive though.
Ciao
Peter |
BretM (Bretm)
Intermediate Member
Username: Bretm
Post Number: 1996
Registered: 2-2001
| | Posted on Wednesday, March 13, 2002 - 8:22 pm: | |
I always forget something, do we have edit anymore in the new format Rob if you're listening?
The sensor is usually cream colored and is held in my two small nuts (studs), they're like 7mm. |
BretM (Bretm)
Intermediate Member
Username: Bretm
Post Number: 1995
Registered: 2-2001
| | Posted on Wednesday, March 13, 2002 - 8:21 pm: | |
The sensor is really easy to get to. Just pull the driver's side wheel and wheelwell, it's sitting right there on the bellhousing (there are three sensors sticking out of it, two on the front side and one on the back near the drunk area, the tach is the one in the back). You actually can get to it from above if you know what you're looking for, it's easier to just go through the wheel well though I'd say. I'm not sure how you would isolate it. They cost about $75 from TRutlands, so if you're looks like it has seen better days it's probably worth replacing. |
Jerry H (Jerry)
Junior Member
Username: Jerry
Post Number: 95
Registered: 3-2001
| | Posted on Wednesday, March 13, 2002 - 8:04 pm: | |
Bret can this change/fix be done without major work or engine pull? Is there anyway to isolate the problem to theis sensor? I would at least like to "half" the problem. |
BretM (Bretm)
Intermediate Member
Username: Bretm
Post Number: 1990
Registered: 2-2001
| | Posted on Wednesday, March 13, 2002 - 7:57 pm: | |
My first impression is tach sensor. 308s had problems with them quite often. I just replaced mine about a month after I took my car off the road. When I got underthere and took it out the wires literally fell off in my hand. Needless to say a new one made a noticeable difference. I don't know the real intracacies of the tach system though, I just know how it works, not what causes certain problems. Just my $.02 |
Jerry H (Jerry)
Junior Member
Username: Jerry
Post Number: 94
Registered: 3-2001
| | Posted on Wednesday, March 13, 2002 - 7:37 pm: | |
Yes, but the reading is not linier. It also appeares to be intermittent but mostly bad. |
Greg Owens (Owens84qv)
Junior Member
Username: Owens84qv
Post Number: 231
Registered: 10-2001
| | Posted on Wednesday, March 13, 2002 - 7:28 pm: | |
Can you give some examples? If you believe the car should be reading 3000rpm, is it really reading 1500? |
Jerry H (Jerry)
Junior Member
Username: Jerry
Post Number: 93
Registered: 3-2001
| | Posted on Wednesday, March 13, 2002 - 7:19 pm: | |
I've searched the previous posts but did not find any solutions to my tach problem. It seems to be reading 2/3 to 1/2 slow, same problem posted previous but I did not see any resolution. This is a recent problem and the previous owner never saw this happen before. The speedo is also showing this symptom. The car starts and drives well as before. Any ideas guys? |