Tach reads much higher by probably a 1000 RPMs (Page 1/1)
72and86 OCT 24, 11:50 AM
Bought a project '86 SE V6. The Tach reads much higher by probably a 1000 RPMs then actual RPM. I've read a lot about this online but can't seem to get a straight answer. What's the definitive fix for this?
Gall757 OCT 24, 12:46 PM
The 'fix' is to send a PM to J Gunsett.

http://www.fiero.nl/forum/Forum2/HTML/140338.html
pmbrunelle OCT 24, 02:16 PM
The fix isn't a J Gunsett exclusive; the RC circuit is fairly well documented.

http://www.nathanbittinger....ction/fieros_de_tach
Gall757 OCT 24, 06:28 PM
If the OP would like someone to fix his tachometer, I recommend J Gunsett.
wftb OCT 24, 06:55 PM
This is only sort of related but the last time I had my guage cluster apart (2004 Cavalier cluster) I managed to knock the tach needle up to 4K rpm .

Recalibrated by just twisting it back to 0. For all I know it might have just recalibrated itself by just turning the car back on but I did not try that.

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86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms

Dennis LaGrua OCT 25, 07:54 AM
I would also check the tach filter. Its basically a capacitor. They can dry out and change values.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

72and86 OCT 25, 10:05 AM
Will this fix it?
https://www.ebay.com/itm/19...L90Z278x5ickk7d4nrem BkvNKtcC0ZwqXDIuFCu5lU%252BLGneSheO3g6w60%252FRvpxvG1GKKBceiBo2eAnKxadQkSfiQ6L%252BkH5%252FbYhz8W6tPeee9oVPPmrLf4DQlu2cXo7R%252BCg7Qc1hv%252BRqLBfUt77GJ8rkSLavY2KbSpTb6141sS94gn5I5xK6hxVJZ%252FyybuRgr4qMiUrsqNIQZV8kKcNiP6HXZTqdNbKeUVU4%252FwqcyeDqjnZAK2BvY veBPscQ1SLKBa%252BBhi7BHO%252FDCBi2%252BxtOavePoE72Mc3CfpfZ%252FXR8Q7VyGbSSwDqcmVSwDwMrSQOHxDNGrTN%252BD0Rqeg%252F2epc3ZEPO7IODwJ%252BiahWRkhrqx6Mgom2%252FD54zleB3D4SJED0X3TJI3MtoLZXuTp%252Bpjriko9Ogw%252BkDe2Y4SRAfgZeAi86208CJ8xTgkFoMyULEWaRhfBC1RYvy2PcrA RG2GFjf9vKQEpYG3bQTNG5ztGe2BWNoYuDxPPwcVoRY833%252BYWKMUEViRJuu2%252Bnsb1C1u9oibUkjsTNrk1MP0HbHR%252FDuYqdHYt6IGerD0jAv3RXBMUpyrQJNslxzawY0rgvq28dUK2s5wqsSkkVnBfc7UC7E3T2RmRJjdYe2YH%252FXPKHUtvCsdBlD4EgE%252FGrZegp0gNX%252BDCv%252F0rU4hT6zdYGs27Fkylbbj6vAq 8xHyT7BuWFgWuyBeraWu02w80GMorgpEmRxzNK3Dw3qFZZSBgRfBYgHf9J6RnsLS4kiX%252BzNd5zb8nVQNzzLP73jPAdJp5%7Ccksum%3A143366400388381c8d17b9f340a6a87ff9e31946fa95%7Campid%3APL_CLK%7Cclp%3A2334524