| Author |
Message |
Henryk (Henryk)
Intermediate Member
Username: Henryk
Post Number: 1055
Registered: 8-2001
| | Posted on Sunday, August 10, 2003 - 4:43 pm: | |
Michael: I think that 3250 RPM @ 75 MPH is right on.......this is what mine shows......3500 is 80 MPH. I had the speedo checked with a radar unit.
I would think the sensor should last longer then that!!!! Possibly the speedo unit itself.....had mine replaced after 19,000 miles. |
Michael N. (Man90tr)
Member
Username: Man90tr
Post Number: 785
Registered: 4-2001
| | Posted on Sunday, August 10, 2003 - 3:16 pm: | |
Thanks Steve,
My injection set up is identical to yours. The 90 and 91's are the same. I have a US TR.
Michael |
Steve Magnusson (91tr)
Intermediate Member
Username: 91tr
Post Number: 2010
Registered: 1-2001
| | Posted on Sunday, August 10, 2003 - 2:21 pm: | |
Michael -- US TRs (KE-Jetronic with lambda) don't have the separate warm-up regulators (when cold, the injection ECUs just send extra current to the EHA valves on the FDs to increase richness) -- what version/injection type is your TR? The EHA valves also control the warm running closed-loop mixtures so since you report warm running is generally OK (and if yours is a US TR) I wouldn't be looking at the EHA stuff yet.
Your low-RPM-after-warm-restart sounds more like a slow/lazy supply-side fuel pressure build-up on one of the banks. Just like those electrical "input" tests, checking/measuring the supply-side fuel pressure is the basic test for the fuel "input" side. You can either buy the JCWhitney Bosch CIS gauge set or pay a shop about the same amount to check. |
Michael N. (Man90tr)
Member
Username: Man90tr
Post Number: 782
Registered: 4-2001
| | Posted on Sunday, August 10, 2003 - 12:50 pm: | |
Thanks everyone.
Henryk,
My speedo just got the sender changed last year (February 2002) -- but that was 13,000 miles ago so it might have gone bad already-- you think?
My fifth is very close to that -I read 80mph at 3250 when it working right -- now at 3250 it reads 75 -- so something is up.
A bit of trivia for you. I tracked 5th gear up to 130 and here is a cool thing to know. Pretty much increases 30 mph every 1000 rpms and 15 mph every 500. At 130 I was at 4800 (just a tick over 4750) Do the extrapolation and you can see where the 180 top speed comes from.
3250 - 80
4250 - 110
5250 - 140
6250 - 170
6750 - 180
Steve,
Maybe a bad warm up regualtor valve? - One thing is that it does not start well when hot -- idles too low when hot unitl I hit the gas and let it run at 1500 or so for about 45 seconds. Then it goes to the 1000 rpms like it should.
Does this sound like it running way too lean at start up to you?
Michael
|
Steve Magnusson (91tr)
Intermediate Member
Username: 91tr
Post Number: 2008
Registered: 1-2001
| | Posted on Sunday, August 10, 2003 - 11:16 am: | |
1. ditto -- replacing the speedometer sensor seems inevitable on TRs. Let me know if you'd like to borrow the wrench to do it "in-situ", or you can make your own per this thread:
http://www.ferrarichat.com/discus/messages/256120/1760.html.
2. I'm not aware of any super-direct speedo-to-tach electrical/physical relationships that would typically cause them to misbehave quasi-simultaneously (but a 1 second tach lag doesn't seem right) -- you could always try checking/refreshing the coils-to-modules connections (and the small round and 9?-pin square connectors under the coolant tank) just on general principles.
3. It's always possible an injection ECU has gone wacko, but decent warm running is a good sign for the injection ECUs. This post (and the post in this post):
http://www.ferrarichat.com/discus/messages/112/272348.html
describe how to check the cold "input" signals/events that should be going on in a US (KE-Jetronic with lambda) TR. Start with those IMO... |
Henryk (Henryk)
Intermediate Member
Username: Henryk
Post Number: 1052
Registered: 8-2001
| | Posted on Sunday, August 10, 2003 - 9:37 am: | |
Probably the beginnings of a failed speedo sensor....very common problem in the TR. Mine was acting like yours, and then got worse.....it turned out to be the sensor.
In 5th gear, my tach reads 3,000 RPM @ 70 MPH; and 2500 RPM @ 60 MPH. |
Michael N. (Man90tr)
Member
Username: Man90tr
Post Number: 778
Registered: 4-2001
| | Posted on Sunday, August 10, 2003 - 5:56 am: | |
Hi guys,
Just recently three things have occurred with my 1990 TR and I would like your suggestons. Car 40,000 miles, last time in shop was March for routine oil/filter. Miles driven since then 3,000.
1. My speedo is a bit lazy. At 3900 rpms in 4th it used to say 70 on the nose. Now it reads 67 or 68. In 3rd at 6800, used to read 100, now reads 95. 5250 in 4th used to be 100 now its 96. Also slow to react when above 80. Sometimes when barely moving, the needle would jump from resting on the needle stop to read 25 and then return.
2. Second issue, may be related. The tach is a bit delayed in reaction. Reads 4500. I hit the gas and it sometimes takes a 1 second pause or so before it moves and then hops up to the proper reading. Always was instant before and smooth.
The tach I believe is still accurate in that I routinely check speed against tach readings with a GPS and I can still call my speeds to the exact mph based on the last set of readings I took in May.
The speedo however where it used to read perfect with the GPS is now off by 3-5 mph depending on speed.
3. At idle upon initial start up, the idle is wandering. If I press the gas and hold 1500 it would rise and fall about 50 - 75 rpms to either side of 1500. Used to be steady as a rock before. Finally settles down when warm, but never did this before.
Remedies I have tried. I have done the prerequiste fusebox adjustment and clip maintenance and have seen no change.
Is there a relay that I should be checking or a specifc fuse that may be the culprit? I want to say its the speedo sending unit for the speedo problem, but these things happened all at once so I suspect something more in common with the above systems.
Thanks in advance for your help.
Michael |