1988 Volkswagen Jetta - Answered Questions & Fixed issues

it wont even crank? tell us more or will it turn over and not start?

NORMAL CONDITION.CHECK SAE OF OIL U PUT IN THE CAR.

You should start by checking the thermostat for the radiator. It controls the flow of coolant to your engine. Turning on the heater allows the coolant to circulate through another type of radiator. You should also check your radiator fluid to make sure you have enough( the fluid should be changed around every 5 years).

check the starter fuse in the car and relay under the hood mabye the wires shorted out

This sounds like a fuel pump or fuel filter problem.The 1988 Jetta has two fuel pumps. The "main" one under the car directly in front of the gas tank on the right hand side. The other fuel pum is in the tank. You can access that fuel pum by removing the round access panel in the trunk towards the back seat. You'll need a fuel pressure gauge. You can usually borrow one from a large auto parts chain store.FUEL DELIVERY & SYSTEM PRESSURESSystem PressureConnect Pressure Gauge (VW 1318) between line from fuel distributor to cold start valve andtest port connection on lower chamber of fuel distributor, using Adapter Fittings (VW 1318/5).Test port is sealed by a threaded plug. Bridge fuel pump relay with Jumper Switch (US 4480/3).1.Disconnect wiring from Differential Pressure Regulator (DPR). Open valve on pressure gauge(points at cold start valve line when open) and activate fuel pump. System pressure must be 75-82 psi (5.3-5.8 kg/cm2 ). If pressure reading is low and fuel pump delivery quantity is good,replace pressure regulator.2.If pressure reading is high, disconnect fuel tank return line from DPR. Repeat test. If reading iscorrect, check for plugged return line. If reading is incorrect with line open, replace DPR.3.Differential Control PressureClose valve on pressure gauge. Activate fuel pump with jumper switch. Leave DPRdisconnected. DPR reading should be 2.9-7.0 psi (.2-.5 kg/cm2 ) less than system pressure. Ifpressure is incorrect, disconnect lower chamber return line and measure volume.1.Close open port to diaphragm pressure regulator. Activate fuel pump with jumper switch. Fuelvolume should be .14-.16 qts. (.13-.15L) for period of one minute. If volume is correct, replaceDPR. If volume is incorrect, replace fuel distributor.2.Close valve on pressure gauge. Install Test Harness (1315A/1) between DPR and vehicleharness. Set multimeter to DCA 200 mA scale. Connect multimeter to test harness. Disconnectwiring to coolant temperature sensor. Connect 15 k/ohm side of Test Resistor (VW 1490) tosensor wiring.3.Turn on ignition and fuel pump. Differential pressure should be 10-17.5 psi (.7-1.2 kg/cm2 )less than system pressure. DPR current should be 50-80 mA. If pressure is incorrect and currentis correct, replace DPR.4.If both pressure and current readings are incorrect, remove test harness from DPR. Ensureresistance of DPR is 17.5-21.5 ohms. If reading is incorrect, replace DPR.5.If reading is correct, check ground from temperature sensor to cold start valve. If ground isgood, check power supply fuse. If fuse is okay, check terminals on ECU connector. If connectoris okay, replace ECU.6.Residual Pressure & Internal Leak TestingOpen valve on pressure gauge. Operate fuel pump for 30 seconds. Pressure can drop to aminimum of 38 psi (2.7 kg/cm2 ) after 10 minutes. If pressure drops below specification, inspectfuel pump check valve and all fuel fittings for leakage.1.NOTE: Pressure and leak testing does not include checking cold startvalve.FUEL INJECTION SYSTEM - BOSCH CIS-E -1988 Volkswagen Jetta Page 1 of 3http://www.ondemand5.com/mric/common/asp/printart.aspx 11/25/2011If there are no leaks, check airflow sensor plate clearance. If plate clearance is correct, replacediaphragm pressure regulator and repeat leak test. If pressure drop is not within specification,replace fuel distributor "O" rings.2.Transfer Pump Delivery VolumeCheck voltage supply to pumps. Connect Jumper Switch (US 4480/3) in place of fuel pumprelay, on relay panel. Remove fuel filler cap. Disconnect and plug off Black fuel line fromsending unit.1.Connect hose to sender port and place in measuring container. Turn on fuel pumps. Minimumtransfer pump delivery volume should be .42 qts. (.4L) in 10 seconds. Reconnect fuel line tosender.2.Main Pump Delivery VolumeCheck transfer pump (if equipped) and fuel filter. Disconnect fuel return line and place inmeasuring container. Switch on fuel pump with jumper switch. Check fuel pump deliveryvolume for 30 second period. Delivery rates are given with voltage reading at pump as volumewill change with different voltages.1.Minimum delivery volume for Fox, Quantum and Quantum Syncro models is .71 qts. (.68L) for30 seconds with reading of 11.4 volts at fuel pump. Minimum delivery volume for other modelsis .62 qts. (.59L) with 11.4 volts at fuel pump.2.Fuel DistributorCheck sensor plate adjusting lever and fuel distributor control piston for smooth operation.Disconnect fuel injector lines at fuel injectors.1.Remove fuel pump relay and bridge fuel pump circuit. Use Jumper Switch (US 4480/3) in placeof fuel pump relay. When pressure has built up, turn off fuel pump. Move sensor plate from restposition to end of travel.2.Uniform resistance should be felt during entire movement. No resistance should be felt onquick return to rest position. Connect injector lines. Install fuel pump relay.3.Injector Quantity ComparisonRemove fuel pump relay, from relay panel, and install Jumper Switch (US 4480/3) in offposition in place of relay. Attach Fuel Quantity Analyzer (US 4480) to bumper and secure inplace. Remove injectors from cylinder head with fuel lines attached. Check and replace fuelinjector "O" rings as necessary.1.Check tightness of injector insert (2-piece inserts). If inserts are loose, remove and cleanthreads. Use sealing compound when installing upper insert. Replace sealing washer that goesagainst cylinder head below lower portion of insert. Lubricate injector "O" rings with gasolineand install injectors, with fuel lines connected, into fuel quantity analyzer tubes.2.Ensure lines are not kinked or bent. Loosen fittings to align fuel lines and retighten. Removerubber boot from airflow sensor housing above sensor plate. Turn and lift setting screw andadjusting slide of Sensor Plate Adjustable Holder (VW 1348/1) into upper position. Thissimulates full throttle operation. See Fig. 11 .3.FUEL INJECTION SYSTEM - BOSCH CIS-E -1988 Volkswagen Jetta Page 2 of 3http://www.ondemand5.com/mric/common/asp/printart.aspx 11/25/2011Fig. 11: Sensor Plate Adjustable Holder (VW 1348/1)Courtesy of AUDI OF AMERICA, INC.Place sensor plate adjustable holder on airflow sensor housing with holder centered over plate.Pointer on edge of holder base must point toward center of fuel distributor. Push adjusting slideof holder down onto stop.4.Turn adjusting screw clockwise until magnetic end touches sensor plate retaining bolt. Activatefuel pump with jumper switch. Turn adjusting screw of holder counterclockwise until any oneinjector starts to deliver fuel. Turn off jumper switch and empty fuel quantity analyzer aftertaking sample.5.Idle injection quantity is measured first. Lifting adjusting slide of holder to first stop simulatesidle position of sensor plate. Activate fuel pump until fuel level reaches 20 ml on scale of anytube.6.Check that all injectors have identical spray patterns that are even and cone-shaped. If not, raisesensor plate up quickly to full lift position and release. Repeat idle quantity test. Compareamounts of fuel delivered by all injectors with analyzer held level. Maximum difference indelivery quantity between injectors is 3.0 ml of fuel.7.If fuel delivery quantity differs between high and low levels by more than 3.0 ml, interchangeinjectors and repeat test. If difference of delivery quantity changes with injectors, replaceinjectors. If difference of delivery quantity does not change with movement of injectors, eitherfuel lines are pinched or fuel distributor is defective.8.Measure full throttle injection quantity. Empty analyzer into fuel tank and reinstall injectors inanalyzer. Lift adjusting slide of holder to last stop to simulate full throttle position of sensorplate. Activate fuel pump with jumper switch until fuel level reaches 80 ml on scale of any tubeof analyzer.9.Check that all injectors have identical spray patterns that are even and cone-shaped. If not, raisesensor plate up quickly to full lift position and release. Repeat full throttle quantity test.Compare amounts of fuel delivered by all injectors with analyzer held level. Maximumdifference in delivery quantity between injectors is 8.0 ml of fuel.10.If fuel delivery quantity differs between high and low levels by more than 8.0 ml, interchangeinjectors and repeat test. If difference of delivery quantity changes with injectors, replaceinjectors. If difference of delivery quantity does not change with movement of injectors, eitherfuel lines are pinched or fuel distributor is defective.11.Check fuel injectors for leakage immediately after delivery quantity test is complete. Set sensorplate in rest position. Activate fuel pump with jumper switch for 2 minutes. Injectors should notdrip. Replace injectors that drip.See image. Fuel filter is probably located on the frame between the engine and fuel tank.

This is likely a faulty coolant temperature sensor. The rest will need to be adjusted properly. I do have manuals for just those systems. If you would like one, let me know. Email me at [email protected] and I can send via email back to you. They cover the entire fuel system, diagnosis and adjustment.

you may find the fuel filter underneath the vehicle near the rear wheel, running low on gas could be the problem, the whirring noise is most likely the fuel pump.....hope this helps.....cheers.

time to put a new tranny in that jet most of the time it costs to much to repair it then replace it i have done may tranny rebuilds and replacements to me i would just tell you to replace it at least you will get a better warrentee and stuff

VW family engine thermostat is behind the lower coolant inlet . It will be either a plastic or aluminum housing.

To find it...open engine lid and look down at bottom of radiator. You will see a rubber hose from the base of the radiator to the engine at the left side looking in. The hose is attached to the housing that holds in the thermostat.

FYI. Never run a VW engine without a thermostat in place or overheating will occur ....really !

1-3-4-2 Distributor rotates clockwise.

Erratic idle is usually due to a broken leaking vaccuum hose. I would start by checking all the small black vaccuum hoses under the hood for cracks. Replace as needed. Thanks for asking at Fixya.com.

time for a new master cylinder

water flange , may be?

replace lock with new one

reset the alarm/immobiliser with the remote/keys.
(if car starts then 2seconds later stops,like you have turned off key.)if batteries in remote are flat,same effect.....

You can take this off and have it checked out at you r local auto shop. Most likely if you're not getting spark, the coil is bad. You can check it yourself through a backyard mechanic way, but it can give you a shock if not careful. ( a screw driver in the end of a plug wire, holding it close to a metal ground while someone turns the engine over. If you see spark, then the coil is good. Be sure to use a screw driver with a good insulated handle.

Take to an independent VW mechanic or a VW dealer. Very difficult job

email me at [email protected] and i do have the diagram and instructions.

temp should stay about half while driving sounds like you have a bad thermostat if guage is half way at idle do you have heat feel both heater hoses should be about same temp if one is cooler not flow coolant

if you are doing all four you make sure the fluid reservoir is full then start with the longest line which is the right rear remove the wheel,find the bleeder nipple on the caliper usually has black rubber cap on it to keep dirt out,remove the cap and unscrew it, now just wait until the fluid starts to flow catch it with a pan.as soon as the air bubbles stop flowing best to wait for 1/4 cup of fluid.tighten the bleeder nipple and go to the other side,repeat this to all wheels,must make sure to keep reservoir full and lid off until done.